Mongoose Query most recent doc w/ a bool value set to false

i'm trying to write a query that chooses the most recently created entry that also has a false value. My schema looks like this:

var EntrySchema = new Schema({
    timestamp: {
        type: Date,
        default: Date.now
    },
    booth: Number,
    used: Boolean,
    strip: String,
    intro: String,
    sess1: String,
    sess2: String,
    sess3: String,
    sess4: String
});

I'm looking to only return ONE entry that has a 'used' key set to false. Any help would be appreciated!

This is what i'm working with now.

Entry.find({used: false}).sort({timestamp:-1}).limit(1).exec( function (err, entrys) { if (err) { return handleError(res, err); } return res.json(200, entrys); } );