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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (557139) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00009

JSON explain

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    "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
557139 This accessory kit is all you need to make your NuWave Brio Air Fryer the complete appliance in your kitchen. The additional rack lets you make the most of your 6 qt. capacity. The baking pan is ideal for eggs, mac and cheese and much more. The 30-recipe cookbook will get you on your way to complete satisfaction! For use with 6-qt. NuWave Brio Air Fryer. <br><br>Dimensions: 8-1/4&quot; W x 5-3/4&quot; H x 7-3/4&quot; D