SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '', 
    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 (4512) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "const",
      "possible_keys": ["PRIMARY", "product_id"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "ref": ["const", "const"],
      "rows": 1,
      "filtered": 100
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text
4512 <p>Carrying cases are available in sizes designed to fit your radio and battery and permit audio to be heard clearly. This hard leather case with 3-inch swivel belt loop is designed to work with the XPR 7350 non-display radio. Swivel model cases secure to a belt loop and allow the case to swing freely from side to side. The swivel latch system also allows the radio and case to be removed from the belt loop by simply inverting the case and lifting it up and out of the belt loop.</p> XPR 7350 Case, XPR 7380 Cases