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 (173787, 173789, 173763) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00078

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "4.21"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 3,
      "rows_produced_per_join": 3,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "3.62",
        "eval_cost": "0.60",
        "prefix_cost": "4.22",
        "data_read_per_join": "20K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_descriptions`.`product_id` in (173787,173789,173763)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
173763 <p>We provide our customers with the "collection of used items". Specialized assembly technicians will go to your home; They will collect the used furniture, making it easier for the customer and at the same time guaranteeing eco-sustainable disposal.</p> <p>Booking the service is very simple and fast.</p> <p><br /></p>
173787 <p>To obtain an efficient and highly professional moving and transport service, it is important to rely on a company capable of making rapid and punctual deliveries and capable of dedicating the utmost attention to detail to each one.</p> <p>Thanks to the professionals of Denis Trasporti & Traslochi it is possible to organize any type of removals and transport even with special vehicles and depending on the type of goods or company. The fundamental element is that the professionals are able to provide all the security guarantees and to perform any service in accordance with the law in order to protect both the cargo and the customer.</p> <p>Booking the service is very simple and fast. For more information please do not hesitate to contact us.<br /></p>
173789 <p>To obtain an efficient and highly professional free moving and transport inspection service, it is important to rely on a capable and efficient company.</p> <p>Thanks to the professionals of Denis Trasporti & Traslochi it is possible to organize any type of removals and transport even with special vehicles and depending on the type of goods or company. The fundamental element is that the professionals are able to provide all the security guarantees and to perform any service in accordance with the law in order to protect both the cargo and the customer.</p> <p>Booking the service is very simple and fast. For further information please do not hesitate to contact us.</p> <p> </p>