SELECT 
  cscart_ult_product_descriptions.product_id, 
  cscart_ult_product_descriptions.short_description, 
  IF(
    cscart_ult_product_descriptions.short_description = "", 
    cscart_ult_product_descriptions.full_description, 
    ""
  ) AS full_description, 
  cscart_ult_product_descriptions.meta_keywords, 
  cscart_ult_product_descriptions.meta_description, 
  cscart_ult_product_descriptions.search_words, 
  cscart_ult_product_descriptions.promo_text 
FROM 
  cscart_ult_product_descriptions 
WHERE 
  cscart_ult_product_descriptions.product_id IN (
    827, 826, 595, 485, 486, 838, 549, 660, 
    546, 1260, 978, 979, 401, 400, 457, 462, 
    516, 564, 321, 989, 987, 988, 748, 502
  ) 
  AND cscart_ult_product_descriptions.company_id = 1 
  AND cscart_ult_product_descriptions.lang_code = 'en'

Query time 0.00126

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_ult_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id", "company_id"],
      "key": "PRIMARY",
      "key_length": "13",
      "used_key_parts": ["product_id", "lang_code", "company_id"],
      "rows": 24,
      "filtered": 100,
      "index_condition": "cscart_ult_product_descriptions.company_id = 1 and cscart_ult_product_descriptions.product_id in (827,826,595,485,486,838,549,660,546,1260,978,979,401,400,457,462,516,564,321,989,987,988,748,502) and cscart_ult_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text
321
400
401
457
462
485
486
502
516
546
549
564
595
660
748
826
827
838
978
979
987
988
989
1260