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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 (
    64531, 63919, 63727, 64535, 64525, 64524, 
    64509, 64424, 64100, 64099, 63197, 
    64508, 64507, 64506, 64505, 64429, 
    64428, 64427, 64426, 64425, 64393, 
    64208, 63573, 63572, 61775, 61755, 
    64145, 64122, 64121, 64120, 61891, 
    64080, 64079, 63775, 63898, 63897, 
    63871, 63718, 63301, 63300
  ) 
  AND cscart_ult_product_descriptions.company_id = 1 
  AND cscart_ult_product_descriptions.lang_code = 'en'

Query time 0.00031

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