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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    20337, 20999, 20206, 21383, 20995, 20590, 
    20207, 20210, 20994, 21401, 21393, 
    20791, 21387, 20478, 20481, 21388, 
    21023, 21024, 21026, 21025, 21028, 
    22540, 22541, 22542, 22543, 22544
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00101

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "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": 26,
          "filtered": 100,
          "index_condition": "cscart_product_descriptions.product_id in (20337,20999,20206,21383,20995,20590,20207,20210,20994,21401,21393,20791,21387,20478,20481,21388,21023,21024,21026,21025,21028,22540,22541,22542,22543,22544) and cscart_product_descriptions.lang_code = 'ru'"
        }
      }
    ]
  }
}