SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.meta_keywords, 
  cscart_product_descriptions.meta_description, 
  cscart_product_descriptions.search_words, 
  cscart_product_descriptions.promo_text, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    10323, 10324, 10325, 10326, 10327, 10328, 
    10329, 10331, 10332, 10333, 10334, 
    10335, 10336, 10337, 10338, 10339, 
    10340, 10341, 10342
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00058

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "rows": 19,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (10323,10324,10325,10326,10327,10328,10329,10331,10332,10333,10334,10335,10336,10337,10338,10339,10340,10341,10342) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}