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 (
    12900, 12904, 12906, 12907, 12908, 12909, 
    12912, 12914, 12925, 12926, 12924, 
    12922, 12918, 12913, 12916, 12930, 
    12923, 12920, 12927, 12917
  ) 
  AND cscart_product_descriptions.lang_code = 'kk'

Query time 0.00338

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 (12900,12904,12906,12907,12908,12909,12912,12914,12925,12926,12924,12922,12918,12913,12916,12930,12923,12920,12927,12917) and cscart_product_descriptions.lang_code = 'kk'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
12900
12904
12906
12907
12908
12909
12912
12913
12914
12916
12917
12918
12920
12922
12923
12924
12925
12926
12927
12930