SELECT 
  SQL_CALC_FOUND_ROWS (
    CASE WHEN products.parent_product_id <> 0 THEN products.parent_product_id ELSE products.product_id END
  ) AS product_id, 
  (
    CASE WHEN descr1.cp_st_h1 <> '' THEN descr1.cp_st_h1 ELSE descr1.product END
  ) AS product, 
  companies.company as company_name, 
  descr1.cp_hash_template_as_timestamp_value, 
  GROUP_CONCAT(
    products.product_id 
    ORDER BY 
      products.parent_product_id ASC, 
      products.product_id ASC
  ) AS product_ids, 
  GROUP_CONCAT(
    products.product_type 
    ORDER BY 
      products.parent_product_id ASC, 
      products.product_id ASC
  ) AS product_types, 
  GROUP_CONCAT(
    products.parent_product_id 
    ORDER BY 
      products.parent_product_id ASC, 
      products.product_id ASC
  ) AS parent_product_ids, 
  products.product_type, 
  products.parent_product_id, 
  1 as instock_marker, 
  IF(
    products.product_type = 'V', 
    IF (
      mccd__variation_stocks.parent_product_id IS NULL, 
      0, 1
    ), 
    IF(
      products.amount > 0, 
      1, 
      IF(products.tracking = 'D', 1, 0)
    )
  ) as instock_sorting, 
  CASE WHEN csc_product_currency_items.currency IS NULL THEN "D" ELSE csc_product_currency_items.currency END as currency, 
  products.amount, 
  products.purchase_qty, 
  products.is_invoice, 
  products.ei_order_id, 
  products.ei_status, 
  products.ei_for_user_id 
FROM 
  cscart_products as products 
  LEFT JOIN cscart_mb_vehicle_listing_index AS mb_vehicle_listing_index ON mb_vehicle_listing_index.product_id = products.product_id 
  LEFT JOIN cscart_mb_salvage_cases AS mb_recaon_visibility_case ON mb_recaon_visibility_case.case_id = mb_vehicle_listing_index.case_id 
  LEFT JOIN cscart_product_descriptions as descr1 ON descr1.product_id = products.product_id 
  AND descr1.lang_code = 'ru' 
  LEFT JOIN cscart_product_prices as prices ON prices.product_id = products.product_id 
  AND prices.lower_limit = 1 
  LEFT JOIN cscart_companies AS companies ON companies.company_id = products.company_id 
  INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  AND cscart_categories.storefront_id IN (0, 1) 
  LEFT JOIN (
    SELECT 
      parent_product_id 
    FROM 
      cscart_products 
    WHERE 
      parent_product_id != 0 
      AND amount > 0 
      AND product_type = 'V' 
    GROUP BY 
      parent_product_id
  ) AS mccd__variation_stocks ON mccd__variation_stocks.parent_product_id = products.parent_product_id 
  LEFT JOIN cscart_csc_product_currency_items as csc_product_currency_items ON csc_product_currency_items.product_id = products.product_id 
  AND csc_product_currency_items.company_id = 0 
  LEFT JOIN cscart_product_features_values AS pfv_28 ON pfv_28.product_id = products.product_id 
  AND pfv_28.feature_id = 28 
WHERE 
  1 
  AND (
    mb_recaon_visibility_case.case_id IS NULL 
    OR mb_recaon_visibility_case.import_source NOT LIKE 'recaon_%' 
    OR mb_vehicle_listing_index.storefront_id = 1
  ) 
  AND (
    mb_recaon_visibility_case.case_id IS NULL 
    OR mb_recaon_visibility_case.selected_flow != 'direct_sale' 
    OR mb_recaon_visibility_case.sale_listing_status != 'hold'
  ) 
  AND companies.status IN ('A', 'S') 
  AND products.company_id IN (1, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 0) 
  AND (
    products.usergroup_ids = '' 
    OR FIND_IN_SET(0, products.usergroup_ids) 
    OR FIND_IN_SET(1, products.usergroup_ids)
  ) 
  AND products.status IN ('A') 
  AND prices.usergroup_id IN (0, 0, 1) 
  AND (
    1 
    AND pfv_28.variant_id = 6795
  ) 
  AND products.is_invoice = 'N' 
  AND products.product_type != 'D' 
GROUP BY 
  product_id 
ORDER BY 
  instock_sorting DESC, 
  products.timestamp desc, 
  products.product_id ASC 
LIMIT 
  1600, 16

Query time 0.35003

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "if(products.product_type = 'V',if(mccd__variation_stocks.parent_product_id is null,0,1),if(products.amount > 0,1,if(products.tracking = 'D',1,0))) desc, products.`timestamp` desc, products.product_id",
      "temporary_table": {
        "filesort": {
          "sort_key": "case when products.parent_product_id <> 0 then products.parent_product_id else products.product_id end",
          "temporary_table": {
            "table": {
              "table_name": "pfv_28",
              "access_type": "ref",
              "possible_keys": [
                "PRIMARY",
                "fl",
                "variant_id",
                "product_id",
                "fpl",
                "idx_product_feature_variant_id"
              ],
              "key": "variant_id",
              "key_length": "3",
              "used_key_parts": ["variant_id"],
              "ref": ["const"],
              "rows": 37073,
              "filtered": 29.32691765,
              "attached_condition": "pfv_28.feature_id = 28"
            },
            "table": {
              "table_name": "products",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "status", "idx_company_id"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["devmotorsbay.pfv_28.product_id"],
              "rows": 1,
              "filtered": 98.33734131,
              "attached_condition": "products.company_id in (1,3,5,6,7,8,10,11,12,13,15,0) and (products.usergroup_ids = '' or find_in_set(0,products.usergroup_ids) or find_in_set(1,products.usergroup_ids)) and products.`status` = 'A' and products.is_invoice = 'N' and products.product_type <> 'D'"
            },
            "table": {
              "table_name": "companies",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "4",
              "used_key_parts": ["company_id"],
              "ref": ["devmotorsbay.products.company_id"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "companies.`status` in ('A','S')"
            },
            "table": {
              "table_name": "prices",
              "access_type": "ref",
              "possible_keys": [
                "usergroup",
                "product_id",
                "lower_limit",
                "usergroup_id"
              ],
              "key": "usergroup",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["devmotorsbay.pfv_28.product_id"],
              "rows": 1,
              "filtered": 99.99243927,
              "attached_condition": "prices.lower_limit = 1 and prices.usergroup_id in (0,0,1)",
              "using_index": true
            },
            "table": {
              "table_name": "mb_vehicle_listing_index",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "4",
              "used_key_parts": ["product_id"],
              "ref": ["devmotorsbay.pfv_28.product_id"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "trigcond(mb_vehicle_listing_index.product_id = products.product_id)"
            },
            "table": {
              "table_name": "mb_recaon_visibility_case",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "4",
              "used_key_parts": ["case_id"],
              "ref": ["devmotorsbay.mb_vehicle_listing_index.case_id"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "trigcond((mb_recaon_visibility_case.case_id is null or mb_recaon_visibility_case.import_source  not like 'recaon_%' or mb_vehicle_listing_index.storefront_id = 1) and (mb_recaon_visibility_case.case_id is null or mb_recaon_visibility_case.selected_flow <> 'direct_sale' or mb_recaon_visibility_case.sale_listing_status <> 'hold')) and trigcond(trigcond(mb_vehicle_listing_index.case_id is not null))"
            },
            "table": {
              "table_name": "products_categories",
              "access_type": "ref",
              "possible_keys": ["PRIMARY", "pt"],
              "key": "pt",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["devmotorsbay.pfv_28.product_id"],
              "rows": 1,
              "filtered": 100
            },
            "table": {
              "table_name": "cscart_categories",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "c_status", "p_category_id"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["category_id"],
              "ref": ["devmotorsbay.products_categories.category_id"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "(cscart_categories.usergroup_ids = '' or find_in_set(0,cscart_categories.usergroup_ids) or find_in_set(1,cscart_categories.usergroup_ids)) and cscart_categories.`status` in ('A','H') and cscart_categories.storefront_id in (0,1)"
            },
            "table": {
              "table_name": "descr1",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "product_id", "idx_product_lang"],
              "key": "PRIMARY",
              "key_length": "9",
              "used_key_parts": ["product_id", "lang_code"],
              "ref": ["devmotorsbay.pfv_28.product_id", "const"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "trigcond(descr1.lang_code = 'ru')"
            },
            "table": {
              "table_name": "<derived2>",
              "access_type": "ref",
              "possible_keys": ["key0"],
              "key": "key0",
              "key_length": "5",
              "used_key_parts": ["parent_product_id"],
              "ref": ["devmotorsbay.products.parent_product_id"],
              "rows": 2,
              "filtered": 100,
              "materialized": {
                "query_block": {
                  "select_id": 2,
                  "filesort": {
                    "sort_key": "cscart_products.parent_product_id",
                    "temporary_table": {
                      "table": {
                        "table_name": "cscart_products",
                        "access_type": "range",
                        "possible_keys": ["idx_parent_product_id"],
                        "key": "idx_parent_product_id",
                        "key_length": "4",
                        "used_key_parts": ["parent_product_id"],
                        "rows": 26,
                        "filtered": 100,
                        "index_condition": "cscart_products.parent_product_id <> 0",
                        "attached_condition": "cscart_products.amount > 0 and cscart_products.product_type = 'V'"
                      }
                    }
                  }
                }
              }
            },
            "table": {
              "table_name": "csc_product_currency_items",
              "access_type": "eq_ref",
              "possible_keys": ["product_id_company_id"],
              "key": "product_id_company_id",
              "key_length": "16",
              "used_key_parts": ["product_id", "company_id"],
              "ref": ["devmotorsbay.pfv_28.product_id", "const"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "trigcond(csc_product_currency_items.product_id = pfv_28.product_id)"
            }
          }
        }
      }
    }
  }
}