I would consider high mileage to be above 50-60K kms.
I sold my P250S with 42K kms, going stronger than ever. At 24K it had major disaster engine failure that was repaired.
Agility 125 has 56K kms, not even a glitch. You would never tell.
These are 4st engines, assuming regular oil changes, not killing them by overheating or revving up high unless they are warmed up, and absence of engine failure due to engineering or assembly mistake, it would be safe to assume that engines can do 80-90k kms without problems. By then, most other things around the scoot would fall apart, the owner would get bored of the scoot or it would be crashed beyond repair.
This is especially relevant for 30 year old and well proven air cooled GY6 engines and derivatives (I think, but I am not sure, that Like also has high displacement GY6).