SELECT DATE_SUB(NOW(), INTERVAL 24*100 HOUR) = DATE_SUB(NOW(), INTERVAL 100 DAY);
How would cutting off anything past 2038 be a real problem when you can be sure that 64bit integer timestamps will be immplemented everywhere 20 years before that at least ?
Seriously, there are so many issues with the datetime / timestamp types in MySQL that you should try and avoid them when possible.
Do you store many dates beyond 2038 ?
And, why not try using PostgreSQL which has much more advanced type support ?