I agree, it's generally not that long to get from check-in to the gates. I generally didn't wait long at the business/elite check-in, and never more than a few minutes at security, but lines at passport control can be quite long - I don't think it took ever more than 20 minutes either, but it does feel a lot longer.
As other poster, I agree the two lounges in Lima are not particularly great, though their (rather well stocked) bars can be a very nice place to have some last pisco sours before flying !