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 (
    89476, 89484, 87449, 88494, 91436, 91450, 
    88446, 88463, 88479, 89020, 89790, 
    88753, 88796, 89785, 85718, 89460, 
    88967, 88968, 88971, 88972, 88955, 
    88956, 88659, 88706, 88167, 88175, 
    88215, 88223, 84774, 84787, 84796, 
    88192, 88204, 88400, 88953, 88954, 
    84769, 84782, 84791, 87879, 88763, 
    85663, 85683, 85695, 85707, 88172, 
    88220, 84778
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00157

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 (89476,89484,87449,88494,91436,91450,88446,88463,88479,89020,89790,88753,88796,89785,85718,89460,88967,88968,88971,88972,88955,88956,88659,88706,88167,88175,88215,88223,84774,84787,84796,88192,88204,88400,88953,88954,84769,84782,84791,87879,88763,85663,85683,85695,85707,88172,88220,84778)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}