It isn't just mutation rate but generation time as well, even with the same mutation rate a virus that replicates several times a day would evolve faster. But there's certainly scope for us to artificially select for traits in virovorous organisms for our own purposes, we commonly do for crop plants to provide viral resistance or tolerance and viruses don't overcome them too quickly. Traditional methods have included x-ray mutagenesis where we crudely induce mutations in a lot of plants and see if any are useful afterward.