SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf9f9de45519b77fc1312949da3417048cab9be5ed73ba064bce6833481c13fc' 
  AND token = 'dgf6AOjPckX+qJQuHLyWAKBhYSKyZBL7tbxelWhk/1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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