SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  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 (
    12928, 12921, 12929, 12910, 12911, 12915, 
    12919, 12931, 12932, 12933, 12934, 
    12935, 12936, 12937, 12938, 12939, 
    12940, 12941, 12942, 13031
  ) 
  AND cscart_product_descriptions.lang_code = 'kk'

Query time 0.00052

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 (12928,12921,12929,12910,12911,12915,12919,12931,12932,12933,12934,12935,12936,12937,12938,12939,12940,12941,12942,13031) and cscart_product_descriptions.lang_code = 'kk'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
12910
12911
12915
12919
12921
12928
12929
12931
12932
12933
12934
12935
12936
12937
12938
12939
12940
12941
12942
13031