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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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (295, 288, 290, 285) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "ALL",
      "possible_keys": ["PRIMARY", "product_id"],
      "rows": 12,
      "filtered": 33.333,
      "attached_condition": "((cscart_product_descriptions.product_id in (295,288,290,285)) and (cscart_product_descriptions.lang_code = 'en'))"
    }
  }
}

Result

product_id	short_description	full_description	meta_keywords	meta_description	search_words
285		<p><b>Holden</b>: Captiva SUV</p> <p><b>Model</b> :</p> <p><b>Year</b>: December 07</p> <p><b>Colour</b>: Silver </p> <p><b>Paint</b> Code:</p> <p><b>Motor</b>:</p> <p><b>Millage</b>: 185694 km</p> <p><b>Vehicle Damage</b></p> <p>Slight front Right</p>	HOLDEN CAPTIVA SILVER SUV 07 WRECKING	HOLDEN CAPTIVA SILVER SUV 07 WRECKING	captiva, silver, 2007, holden
288	<p></p><p>2005 HOLDEN ADVENTRA</p> <p>AUTO V6 260,433kms</p>				VZ,ADVENTRA,HOLDEN
290	<p>2012 Holden Captiva V6 Auto</p>				Holden,Captiva,Black
295		<p>Wrecking 1992 Holden Rodeo 4cyl Petrol Auto 357,626kms</p>	Rodeo, White rodeo, wrecking white holden rodeo,		Wrecking 1992 Holden, Rodeo,4cyl,Petrol,Auto