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 (
    95626, 95627, 95628, 95764, 95766, 95767, 
    95780, 95781, 95782, 95783, 95784, 
    95785, 95829, 95890, 95893, 95925, 
    95926, 95927, 95928, 95929, 95930, 
    95931, 96490, 96491, 96492, 96493, 
    96494, 96495, 96496, 96497
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00053

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 (95626,95627,95628,95764,95766,95767,95780,95781,95782,95783,95784,95785,95829,95890,95893,95925,95926,95927,95928,95929,95930,95931,96490,96491,96492,96493,96494,96495,96496,96497)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
95626
95627
95628
95764
95766
95767
95780
95781
95782
95783
95784
95785
95829
95890
95893
95925
95926
95927
95928
95929
95930
95931
96490
96491
96492
96493
96494
96495
96496
96497