Как правильно вызывать исключения в обработчике запросов mysql в express.js?

router.get('/user/:userId', (req, res) => {
  // let sid = req.query.sid
  const {db} = req.app.locals;

  db.query('SELECT * FROM `users` WHERE `id`=' + req.params.userId, (error, results, fields) => {
    if (error) {
      throw error
    }
    if (results.length) {
      res.send(results)
    } else {
      throw new Error("User not found.")
    }
  })

})

D:\Project\vopen\server\node_modules\mysql\lib\protocol\Parser.js:437
      throw err; // Rethrow non-MySQL errors
      ^

Error: User not found.
    at Query.db.query (D:\Project\vopen\server\routers\users\index.js:16:11)
    at Query.<anonymous> (D:\Project\vopen\server\node_modules\mysql\lib\Connection.js:525:10)
    at Query._callback (D:\Project\vopen\server\node_modules\mysql\lib\Connection.js:491:16)
    at Query.Sequence.end (D:\Project\vopen\server\node_modules\mysql\lib\protocol\sequences\Sequence.js:83:24)
    at Query.ErrorPacket (D:\Project\vopen\server\node_modules\mysql\lib\protocol\sequences\Query.js:90:8)
    at Protocol._parsePacket (D:\Project\vopen\server\node_modules\mysql\lib\protocol\Protocol.js:291:23)
    at Parser._parsePacket (D:\Project\vopen\server\node_modules\mysql\lib\protocol\Parser.js:433:10)
    at Parser.write (D:\Project\vopen\server\node_modules\mysql\lib\protocol\Parser.js:43:10)
    at Protocol.write (D:\Project\vopen\server\node_modules\mysql\lib\protocol\Protocol.js:38:16)
    at Socket.<anonymous> (D:\Project\vopen\server\node_modules\mysql\lib\Connection.js:91:28)