First user checks the restaurant is existed or not in this website. If it is available he will think about more options like filters.
These kind of search is not only useful for whose want to search by the time, location, combinations,.. different kind of user will come with their different requirements.
In case, if you have provided filters such as location, time, combinations,... fields in main search, the process may take time to get results. User may not be wait. We need to consider low bandwidth also.
We can see the mobile, travels,.. search as a example. Some are provides filters in left panel of searched results.
So think yourself which is fit for your requirements.