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 (
    95910, 95911, 95912, 95913, 95914, 95915, 
    95916, 95917, 95918, 95919, 95920, 
    95921, 95922, 95923, 95924, 95945, 
    95946, 96119, 96508, 96530, 96570, 
    96572, 96573, 97574, 97575, 97608, 
    97610, 97611, 97612, 97613
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00073

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 (95910,95911,95912,95913,95914,95915,95916,95917,95918,95919,95920,95921,95922,95923,95924,95945,95946,96119,96508,96530,96570,96572,96573,97574,97575,97608,97610,97611,97612,97613)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
95910
95911
95912
95913
95914
95915
95916
95917
95918
95919
95920
95921
95922
95923
95924
95945
95946
96119
96508
96530
96570
96572
96573
97574
97575
97608
97610
97611
97612
97613