SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '881a06eb8c3ff5b88f79a3db1445c63cd1f3901798abaf294bd66f16f2b68f95' 
  AND token = 'q/yEqK8hx7tG6/G8IvQtJ3khjY7vxw+3sHlDQjqLhg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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