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 (
    85506, 85508, 90871, 90872, 90950, 90951, 
    82624, 83489, 85096, 82579, 82795, 
    82796, 82868, 82869, 82941, 82942, 
    83153, 83154, 83158, 83159, 83267, 
    91088, 91174, 91229, 83555, 83556, 
    85116, 85117, 88893, 88894, 89834, 
    89835, 89886, 89887, 89958, 89959, 
    91462, 91463, 91466, 91467, 91524, 
    91525, 83573, 86490, 86766, 85304, 
    85401, 85452
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00108

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "25.94"
    },
    "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": "21.14",
        "eval_cost": "4.80",
        "prefix_cost": "25.94",
        "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 (85506,85508,90871,90872,90950,90951,82624,83489,85096,82579,82795,82796,82868,82869,82941,82942,83153,83154,83158,83159,83267,91088,91174,91229,83555,83556,85116,85117,88893,88894,89834,89835,89886,89887,89958,89959,91462,91463,91466,91467,91524,91525,83573,86490,86766,85304,85401,85452)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}