Using Memoizee with node.js

I want to use Memoizee on my node.js backend, to speed up the requests.

But for some reason, I can't get it to work like I want to. I have a route, that waits for the callback of another method, but no matter how long I save the result in cache, it runs the whole method every time.

What am I doing wrong?

Here is an example of my implementation.

var memoize = require('memoizee');

module.exports = function (app) {

app.route('/someurl/:user_id')
    .get(function (req, res) {

        var user_id = req.params.user_id;

        memoized(user_id, function (result) {      
            res.send(result)
        })
    });
};

var doWork = memoize(function(user_id, done) {
    //Handling a lot of data - takes about 10-15 seconds
    done(index);
});

var memoized = memoize(doWork, {maxAge: 300000});