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 (
    12965, 12961, 12963, 12968, 12967, 12969, 
    17761, 17762, 17763, 17764, 17765, 
    17766, 17767, 17768, 17769, 17770, 
    17771, 12970, 12972, 12973
  ) 
  AND cscart_product_descriptions.lang_code = 'kk'

Query time 0.00041

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 (12965,12961,12963,12968,12967,12969,17761,17762,17763,17764,17765,17766,17767,17768,17769,17770,17771,12970,12972,12973) and cscart_product_descriptions.lang_code = 'kk'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
12961
12963
12965
12967
12968
12969
12970
12972
12973
17761
17762
17763
17764
17765
17766
17767
17768
17769
17770
17771