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 (
    95255, 95256, 95257, 95258, 95259, 95260, 
    95261, 95262, 95263, 95264, 95265, 
    95266, 95267, 95268, 95269, 95270, 
    95271, 95272, 95273, 95274, 95275, 
    95276, 95277, 95278, 95279, 95280, 
    95281, 95282, 95283, 95284
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00085

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 (95255,95256,95257,95258,95259,95260,95261,95262,95263,95264,95265,95266,95267,95268,95269,95270,95271,95272,95273,95274,95275,95276,95277,95278,95279,95280,95281,95282,95283,95284)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
95255
95256
95257
95258
95259
95260
95261
95262
95263
95264
95265
95266
95267
95268
95269
95270
95271
95272
95273
95274
95275
95276
95277
95278
95279
95280
95281
95282
95283
95284