SELECT 
  q_product_descriptions.product_id, 
  q_product_descriptions.short_description, 
  IF(
    q_product_descriptions.short_description = '', 
    q_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  q_product_descriptions 
WHERE 
  q_product_descriptions.product_id IN (
    571, 572, 573, 574, 575, 576, 577, 578, 
    579, 580, 551, 552, 553, 554, 555, 556
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00086

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "38.41"
    },
    "table": {
      "table_name": "q_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": 16,
      "rows_produced_per_join": 16,
      "filtered": "100.00",
      "index_condition": "((`portal`.`q_product_descriptions`.`product_id` in (571,572,573,574,575,576,577,578,579,580,551,552,553,554,555,556)) and (`portal`.`q_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "35.21",
        "eval_cost": "3.20",
        "prefix_cost": "38.41",
        "data_read_per_join": "61K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ]
    }
  }
}

Result

product_id short_description full_description
551
552
553 <p>Roberto Cavalli launched a new fragrance in 2012, simply named Roberto Cavalli Eau de Parfum. It is created for women who want to be noticed and who prefer to wear Cavalli animal print dresses. The fragrance is an intense oriental - floral and is based on notes of orange blossom, symbolizing Italian femininity, sensuality and extravagance. There are also ambery - oriental nuances of benzoin, pink pepper, tonka and vanilla. The composition is developed by Louise Turner of Givaudan. Model and actress Elisa Sednaoui is the muse of this fragrance. The bottle is round topped with a tiara shaped stopper containing the designer's initials. Golden shades and leopard print decorate the bottle design and packaging.</p>
554
555
556
571
572
573
574
575
576
577
578
579
580