How to access the searched sub-fragment in a mongodb query (using Mongoose)

I have a fairly simple collection:

var Access = new Schema({
  userId         : { type: ObjectId, index: true },
  token          : { type: String, index: true },
  isOwner        : { type: Boolean, index: true },
});
mongoose.model('Access', Access);

var Workspace = new Schema({
  name           : { type: String, lowercase: true, unique: true},
  description    : String,
  isActive       : Boolean,
  settings       : {
    longName        : String,
    welcomeMessage  : String,
    countryId       : { type: ObjectId, index: true },
  },
  access          : [ Access ],
});
mongoose.model('Workspace', Workspace);

When a user connect, I have a middleware check the token and see if everything is OK. So, I have:

exports.tokenCall = function( req, res, next, token ){

  var Workspace = mongoose.model('Workspace'),
      User = mongoose.model('User'),
      accessEntry;

  req.application = {};

  // Find the token
  Workspace.findOne({ 'access.token': token } , function(err, doc){
    if(err){
      next( new g.errors.RuntimeError503( err ) );
    } else {
      if(! doc ){
        next( new g.errors.BadtokenError403() );
      } else {
        accessEntry = doc.access.filter(function(entry){ return entry.token == token;  } )[0];

        req.application.workspaceId = doc._id;
        req.application.workspaceName = doc.name;
        req.application.userId = accessEntry.userId;
        req.application.login =  accessEntry.login;
        req.application.token = token;
        req.application.workspace = doc; // Contains all of the settings!
        next();
      }
    }
  });
}

I am sure you can see my problem here: I run Workspace.findOne({ 'access.token': token } , function(err, doc){ to find the document with the right token. But THEN, I am actually... searching an array (!) to find the actual token I looked for! accessEntry = doc.access.filter(function(entry){ return entry.token == token; } )[0]; I am sure this is not the way to do this -- surely. What if I make a query 4 levels down...?!?

So, what is the right way of doing this?