"Increased security" in Brazil means now equal to that "before" in most major EU/US/CDN airports, so arrival time should be equal, 2 hours minimum before boarding time, IMO, more if possible. You must take traffic into consideration when deciding when to leave your lodging. If at a hotel, staff can be helpful at estimating time in traffic at a given hour. It's not an exciting airport in terms of shopping or restaurants, but bring a book or your internet device to pass the time and you'll be OK, or decide to eat dinner/snack there.