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 (
    9814, 9815, 9816, 9817, 9818, 15732, 
    9820, 9821, 9822, 9823, 9824, 9825, 
    9826, 9827, 9828, 9829, 9830, 10241, 
    10243, 10244
  ) 
  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": 20,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (9814,9815,9816,9817,9818,15732,9820,9821,9822,9823,9824,9825,9826,9827,9828,9829,9830,10241,10243,10244) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}