You may only hold 5 tokens at once.(Yes, these tokens DO work on the War Pegasus.)
Items purchased through an LTO will allow you to exceed the in game limits. You just will not be able to redeem/earn more in game until you drop back below the limit.So if you bought all 5 of those, you would be at 20/5. And then if there were some available as prizes in the raid, you would not be able to get them until you use some and get down to below the cap.