You need to be at the gate 30 minutes before departure-
https://www.ana.co.jp/wws/ca/e/asw_c...n/checkin.html.
The security line is pretty short, I would arrive 45-50 minutes before departure. It only took me 5 minutes to go through the line last time I was there.
If you have time there is a bagel shop between the ANA and JAL side that is pretty good past security