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 (
    83590, 90867, 90869, 90946, 90948, 82623, 
    83012, 83013, 83488, 83544, 83545, 
    90845, 90846, 90924, 90925, 85070, 
    85156, 85202, 85248, 85113, 88895, 
    90823, 91464, 91465, 91468, 91469, 
    83233, 83234, 83028, 83581, 90012, 
    90740, 90741, 90864, 90943, 82843, 
    82916, 82989, 83473, 83481, 85110, 
    84510, 84514, 84576, 84580, 83293, 
    83300, 84884
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00115

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "27.01"
    },
    "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": "22.21",
        "eval_cost": "4.80",
        "prefix_cost": "27.01",
        "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 (83590,90867,90869,90946,90948,82623,83012,83013,83488,83544,83545,90845,90846,90924,90925,85070,85156,85202,85248,85113,88895,90823,91464,91465,91468,91469,83233,83234,83028,83581,90012,90740,90741,90864,90943,82843,82916,82989,83473,83481,85110,84510,84514,84576,84580,83293,83300,84884)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}