Sandbox

SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    87012, 87013, 87014, 87015, 87016, 87017, 
    87072, 87073, 87074, 87075, 87076, 
    87077
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00064

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "5.41"
    },
    "table": {
      "table_name": "cscart_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": 12,
      "rows_produced_per_join": 12,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "4.21",
        "eval_cost": "1.20",
        "prefix_cost": "5.41",
        "data_read_per_join": "45K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (87012,87013,87014,87015,87016,87017,87072,87073,87074,87075,87076,87077)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id	short_description	full_description
87012	Old London Floor Standing 2 Door Vanity Unit with 1 Tap Hole White Marble Top 1000mm - Twilight Blue
87013	Old London Old London Twilight Blue Floor Standing 2 Door Vanity Basin Unit with Square Basin & 1 Tap Hole Marble Top, 1000mm - Twilight Blue
87014	Old London Floor Standing 2 Door Vanity Unit with 1 Tap Hole Grey Marble Top 1000mm - Twilight Blue
87015	Old London Floor Standing 2 Door Vanity Unit with 3 Tap Hole Black Marble Top 1000mm - Twilight Blue
87016	Old London Floor Standing 2 Door Vanity Unit with 1 Tap Hole White Marble Top 1000mm - Twilight Blue
87017	Old London Floor Standing 2 Door Vanity Unit with 3 Tap Hole Grey Marble Top 1000mm - Twilight Blue
87072	Old London Floor Standing 2 Door Vanity Unit with 1 Tap Hole Black Marble Top 1000mm - Timeless Sand
87073	Old London Floor Standing 2 Door Vanity Unit with 1 Tap Hole White Marble Top 1000mm - Timeless Sand
87074	Old London Old London Timeless Sand Floor Standing 2 Door Vanity Basin Unit with Square Basin & 1 Tap Hole Marble Top, 1000mm - Timeless Sand
87075	Old London Floor Standing 2 Door Vanity Unit with 1 Tap Hole Grey Marble Top 1000mm - Timeless Sand
87076	Old London Floor Standing 2 Door Vanity Unit with 3 Tap Hole Black Marble Top 1000mm - Timeless Sand
87077	Old London Floor Standing 2 Door Vanity Unit with 1 Tap Hole White Marble Top 1000mm - Timeless Sand