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 (
    29201, 29202, 29203, 29204, 29205, 29206, 
    29207, 29208, 29209, 29210, 29211, 
    29212, 29213, 29214, 29215, 29216, 
    29218, 29219, 29220, 29221, 29222, 
    29223, 29224, 29225, 29226, 29227, 
    29228, 29229, 29230, 29231, 29232, 
    29233
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00115

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 (29201,29202,29203,29204,29205,29206,29207,29208,29209,29210,29211,29212,29213,29214,29215,29216,29218,29219,29220,29221,29222,29223,29224,29225,29226,29227,29228,29229,29230,29231,29232,29233)) 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"
      ]
    }
  }
}