Asfiya is an Arabic and Urdu name that means "pure ones", it is the plural of Safee ("pure"). Mariyam is the name of the mother of Prophet Isa peace be upon them and may mean "beloved" or "wished for child", though the meaning is not known for certain by anyone. Asfiya should not be spelled as Asfiyah since it does not have an "h" sound at the end, it is not like Fatima which can be written as Fatimah. Asfiya can be written as Asfiyaa, but not Asfiyah.
Asfiya Mariyam is a good name and you can use it insha'Allah.