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 (
    14849, 14850, 14851, 14852, 14853, 14855, 
    14858, 14860, 14861, 14862, 14875, 
    14880, 14881, 14894, 14933, 15229, 
    15284, 15285, 15288, 15519, 15712, 
    15713, 15726, 15772, 15778, 15837, 
    15866, 15867, 15868, 15872
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00075

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "72.01"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "index_condition": "((`portal`.`q_product_descriptions`.`product_id` in (14849,14850,14851,14852,14853,14855,14858,14860,14861,14862,14875,14880,14881,14894,14933,15229,15284,15285,15288,15519,15712,15713,15726,15772,15778,15837,15866,15867,15868,15872)) and (`portal`.`q_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "66.01",
        "eval_cost": "6.00",
        "prefix_cost": "72.01",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ]
    }
  }
}