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 (
    95869, 95870, 95871, 95872, 95873, 95874, 
    95875, 95876, 95877, 95878, 95879, 
    95880, 95881, 95882, 95883, 95884, 
    95890, 95893, 95895, 95896, 95897, 
    95898, 95899, 95900, 95901, 95902, 
    95903, 95904, 95905, 95906
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00064

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 (95869,95870,95871,95872,95873,95874,95875,95876,95877,95878,95879,95880,95881,95882,95883,95884,95890,95893,95895,95896,95897,95898,95899,95900,95901,95902,95903,95904,95905,95906)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
95869
95870
95871
95872
95873
95874
95875
95876
95877
95878
95879
95880
95881
95882
95883
95884
95890
95893
95895
95896
95897
95898
95899
95900
95901
95902
95903
95904
95905
95906