SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64c17cb3436dc319732028df3a4f43f655ffb328a26c1a98a65e23a30c09da2c' 
  AND token = 'Vbrt79X0YSsYX1NQZ2HHRXUdXUusPs3esbbxjftpE1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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