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 (
    8440, 8441, 8442, 8443, 8444, 8445, 8446, 
    8447, 8449, 8450, 8451, 8452, 8453, 
    8454, 8455, 8457, 8458, 8459, 8460, 
    8461, 8462, 8463, 8464, 8465, 8466, 
    8467, 8468, 8469, 8470, 8471, 8472, 
    8473
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00072

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 (8440,8441,8442,8443,8444,8445,8446,8447,8449,8450,8451,8452,8453,8454,8455,8457,8458,8459,8460,8461,8462,8463,8464,8465,8466,8467,8468,8469,8470,8471,8472,8473)) 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"
      ]
    }
  }
}