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 (
    93282, 93284, 93286, 93288, 93290, 93294, 
    93338, 93339, 94428, 94750, 94759, 
    94760, 94761, 94763, 94765, 94816, 
    94950, 94951, 94956, 94957, 95566, 
    95569, 95571, 95574, 95575, 95578, 
    95579, 95580, 95581, 95587
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00084

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 (93282,93284,93286,93288,93290,93294,93338,93339,94428,94750,94759,94760,94761,94763,94765,94816,94950,94951,94956,94957,95566,95569,95571,95574,95575,95578,95579,95580,95581,95587)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
93282
93284
93286
93288
93290
93294
93338
93339
94428
94750
94759
94760
94761
94763
94765
94816
94950
94951
94956
94957
95566
95569
95571
95574
95575
95578
95579
95580
95581
95587