You don't provide the name of your departure airport, but simply build in the time to physically check in with an agent based on your knowledge of that airport or the recommended check-in time. The counter agent will verify your passport and possibly other documents such as a visa if you are required to have one.

Presuming everything is in order, this should add about an extra 30 seconds to the process. If it isn't in order, you won't be flying so it really doesn't make any difference.