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 (
    94443, 94444, 94445, 94446, 94592, 94593, 
    94594, 94650, 94662, 94814, 94815, 
    94837, 95443, 95444, 95445, 95446, 
    95447, 95791, 95792, 95793, 95794, 
    95795, 95796, 95797, 95798, 95799, 
    95800, 95801, 95802, 95804
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00071

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 (94443,94444,94445,94446,94592,94593,94594,94650,94662,94814,94815,94837,95443,95444,95445,95446,95447,95791,95792,95793,95794,95795,95796,95797,95798,95799,95800,95801,95802,95804)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
94443
94444
94445
94446
94592
94593
94594
94650
94662
94814
94815
94837
95443
95444
95445
95446
95447
95791
95792
95793
95794
95795
95796
95797
95798
95799
95800
95801
95802
95804