SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dca9eaf34068f1cf3a66a4902b497254dccdf1e2586dd159bd8bd2352a20ff3' 
  AND token = 'OQTViUiX4KI4wkHQh6V9EHVI1B7x1/wgsOJpLOBYcoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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