SELECT 
  product_id 
FROM 
  cscart_mb_ali_products 
WHERE 
  product_id IN (
    20333, 20334, 20335, 20336, 20337, 20338, 
    20339, 20340, 20341, 20342, 20343, 
    20344, 20345, 20346, 20347, 20348
  )

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_mb_ali_products",
      "access_type": "range",
      "possible_keys": ["product_id"],
      "key": "product_id",
      "key_length": "4",
      "used_key_parts": ["product_id"],
      "rows": 16,
      "filtered": 100,
      "attached_condition": "cscart_mb_ali_products.product_id in (20333,20334,20335,20336,20337,20338,20339,20340,20341,20342,20343,20344,20345,20346,20347,20348)",
      "using_index": true
    }
  }
}