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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 (
    13878, 13877, 13876, 13875, 13874, 13873, 
    13872, 13870, 13869, 13829, 13862, 
    13858, 13850, 13849, 13848, 13847, 
    13846, 13845, 13844, 13843, 13842, 
    13841, 13840, 13839, 13838, 13837, 
    13836, 13835, 13834, 13833, 13832, 
    13831, 13830, 13827, 13826, 13825, 
    13824, 13823, 13822, 13821
  ) 
  AND cscart_ult_product_descriptions.company_id = 1 
  AND cscart_ult_product_descriptions.lang_code = 'en'

Query time 0.00026

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