It's fix at 30 years. Same as KFC. The reason they lock you for 30 years its because they are the one forking out cost to build the drive through, so all cost and risk is taken into consideration hence the 30 years lease.

So, if you think 30 years is too long, then you put discuss an option for them, to sell the land on the 15th year back to the franchisee. Franchisee can buy the land and own it to run the outlet.

For rental amount, cant comment much as too limited info on your land. You can ask around for the rental market, or use valuer to access the rental value for you and negotiate with them, since they are the one approaching you.

If you have plans to develop it on your own, then just scrap off this plan.

BUT, if you can develop a commercial buildings on your own say a row (5 units) of 2 storey shops, you can negotiate and rent the building to them with much more higher rental AND without them locking you for 30 years. You can rent to them for say 10 years on 4+3+3.