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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 (
    12138, 12137, 12136, 12134, 12133, 12132, 
    12129, 12128, 12127, 12096, 12092, 
    12187, 12083, 31084, 31083, 31082, 
    31081, 31080, 31079, 31078, 31077, 
    31076, 31075, 31074, 31073, 31072, 
    31071, 31070, 31069, 31068, 31067, 
    31066, 31065, 31064, 31063, 31062, 
    31061, 31060, 12060, 12073
  ) 
  AND cscart_ult_product_descriptions.company_id = 1 
  AND cscart_ult_product_descriptions.lang_code = 'en'

Query time 0.00034

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	cscart_ult_product_descriptions	ALL	PRIMARY,product_id,company_id				1	Using where