SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d43ede70b2998a20b1eb0a3b35a7bfc5f21449c5b843ff5fe0db99d7dcc5c76' 
  AND token = 'gOdDTqWUeCb+ghDBSJqYZgaDv6ttfQtaD1leJmDTeTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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