What is a good clear coat that I can paint on rather than spray on?

I painted over a cardboard candy box recently. I just used acrylic craft paint, so it's very easy to scratch off. I want to seal it with a clear coat so that it won't come off and so it will be really shiny, but I don't want to use a spray clear coat. Are there any good types/brands of paint-on clear coat that would work well for such a project??