I just redeemed two sets of five, and I’m still at 185. Spending them works fine; decreases the count. But there doesn’t seem to be a way to increase them anymore. Kinda worried on that, because it dovetails with my “never spend a limited resource” habit.
There seem to be some problems currently with key redemption across multiple platforms, especially (but possibly not exclusively?) if the codes are being redeemed through the VIP web site while the player has the game currently running.
There is also an in-game issue with the code used to display the number of keys in hand, which caps out at 255. One fix behind the scenes for this was that the display would not update beyond a certain value (I think somewhere around 230?) until keys had been spent to drop the total below about 200. You should be below that point, though, so I don’t think that’s the issue.
If fully quitting and restarting the game doesn’t trigger an update, but the redemptions are showing in the Rewards tab of the in-game Shift dialog, you’ll need to file a support ticket ticket for assistance. Please let the support team know how you redeemed the key codes (in-game, shift site, VIP site.)