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 (
    95350, 95351, 95353, 95354, 95355, 95514, 
    95515, 95516, 95520, 95521, 95522, 
    95530, 95531, 95532, 95546, 95547, 
    95548, 96190, 96783, 96784, 96807, 
    96808, 96809, 96810, 96811, 96812, 
    96813, 96814, 96815, 96816
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00079

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (95350,95351,95353,95354,95355,95514,95515,95516,95520,95521,95522,95530,95531,95532,95546,95547,95548,96190,96783,96784,96807,96808,96809,96810,96811,96812,96813,96814,96815,96816)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
95350
95351
95353
95354
95355
95514
95515
95516
95520
95521
95522
95530
95531
95532
95546
95547
95548
96190
96783
96784
96807
96808
96809
96810
96811
96812
96813
96814
96815
96816