SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c902066d35647f1fc7208be76f8714530d8e9d9052c6cb16db04842bbb011820' 
  AND token = 'KzJpKkrXdYc8Yy648izYC9p19MU0WXscAb0wfTlMdxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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