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 (
    29301, 29302, 29303, 29304, 29305, 29306, 
    29307, 29308, 29309, 29310, 29311, 
    29312, 29313, 29314, 29315, 29316, 
    29317, 29318, 29319, 29320, 29321, 
    29322, 29323, 29324, 29325, 29326, 
    29327, 29328, 29329, 29330, 29331, 
    29332
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00083

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "76.81"
    },
    "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": 32,
      "rows_produced_per_join": 32,
      "filtered": "100.00",
      "index_condition": "((`portal`.`q_product_descriptions`.`product_id` in (29301,29302,29303,29304,29305,29306,29307,29308,29309,29310,29311,29312,29313,29314,29315,29316,29317,29318,29319,29320,29321,29322,29323,29324,29325,29326,29327,29328,29329,29330,29331,29332)) and (`portal`.`q_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "70.41",
        "eval_cost": "6.40",
        "prefix_cost": "76.81",
        "data_read_per_join": "122K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ]
    }
  }
}