You can always filter on the client side:

    var query = wp.media.query();
    
    query.filterWithIds = function(ids) {
        return _(this.models.filter(function(c) { return _.contains(ids, c.id); }));
    };
    
    var res = query.filterWithIds([6,87]); // change these to your IDs
    
    res.each(function(v){
        console.log( v.toJSON() );
    });

**Disclaimer:** found the beautiful `filterWithIds` function in [this SO question][so].

  [so]: https://stackoverflow.com/questions/6442689/backbone-js-how-do-i-filter-a-collection-of-objects-by-an-array-of-model-ids "Backbone.js: How do I filter a collection of objects by an array of model IDs?"