// ...
var proxyServer = httpProxy.createServer({
  ssl: {
    key: fs.readFileSync('valid-ssl-key.pem', 'utf8'),
    cert: fs.readFileSync('valid-ssl-cert.pem', 'utf8')
  },
  target: 'https://localhost:9010',
  secure: true // Depends on your needs, could be false.
});

proxyServer.listen(443, function listening(err){
  console.log('Server listening');
});