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 (
    83485, 83486, 89800, 89852, 89924, 83065, 
    83618, 90901, 90980, 85133, 85373, 
    85076, 85077, 85162, 85163, 85208, 
    85209, 85254, 85255, 83035, 83036, 
    83307, 83592, 83593, 90871, 90872, 
    90950, 90951, 85116, 85117, 83573, 
    86485, 86654, 86723, 86761, 82628, 
    82629, 83493, 83494, 89748, 82618, 
    83421, 86624, 86625, 86693, 86694, 
    86519, 86795
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00098

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 (83485,83486,89800,89852,89924,83065,83618,90901,90980,85133,85373,85076,85077,85162,85163,85208,85209,85254,85255,83035,83036,83307,83592,83593,90871,90872,90950,90951,85116,85117,83573,86485,86654,86723,86761,82628,82629,83493,83494,89748,82618,83421,86624,86625,86693,86694,86519,86795)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}