Well if it came down to it you’d just have to get the lease extended before you sold if there was only a short amount left.
If there were , say , 72 years or more left it would be the buyers problem.
If the lease had, say, 68 years left, you’d probably pay a contribution to what it would cost...
You don’t need to concern yourself with this for a long long time.
Even with 74 years left you still wouldn’t have anything to worry about for quite a long time.
And it wouldn’t drastically reduce the value anyway.
Relax and forget about it.