SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    22079, 22080, 22081, 22082, 22083, 22084, 
    22085, 22086, 22087, 22088, 22089, 
    22090, 22091, 22092, 22093, 22094
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id", "idx_product_lang"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "rows": 16,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (22079,22080,22081,22082,22083,22084,22085,22086,22087,22088,22089,22090,22091,22092,22093,22094) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}