SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3678d04fcd5202109bc0c9ff36e932989cc1fce7a621c0fe9aa633b6285b3d5' 
  AND token = 'BLYqu9iurjjHomrYzD7euhzFIBtdf/+Clu5azTT31AI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}