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 (
    95798, 95799, 95800, 95801, 95802, 95804, 
    95806, 95808, 95810, 95812, 96564, 
    96565, 96566, 96567, 96568, 97716, 
    97717, 97718, 97774, 97786, 98146, 
    98148, 98152, 98155, 98407, 98408, 
    98409, 98410, 98552, 98553, 98554, 
    98555, 98556, 98763, 98764, 98765, 
    98766, 98767, 98768, 98818, 98822, 
    98826, 98830, 98859, 98860, 98861, 
    98862, 98863
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00103

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (95798,95799,95800,95801,95802,95804,95806,95808,95810,95812,96564,96565,96566,96567,96568,97716,97717,97718,97774,97786,98146,98148,98152,98155,98407,98408,98409,98410,98552,98553,98554,98555,98556,98763,98764,98765,98766,98767,98768,98818,98822,98826,98830,98859,98860,98861,98862,98863)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
95798
95799
95800
95801
95802
95804
95806
95808
95810
95812
96564
96565
96566
96567
96568
97716
97717
97718
97774
97786
98146
98148
98152
98155
98407
98408
98409
98410
98552
98553
98554
98555
98556
98763
98764
98765
98766
98767
98768
98818
98822
98826
98830
98859
98860
98861
98862
98863