Hi Piyush,
You cannot directly use mapname.keyset() or mapname.values() in dynamic queries as dynamic query doesnt allow to map methods to be used in it.
For this you need to fill all the keys or values in a set or list and then IN check to query filterd data
For ex.
set<string> mapkeys=new set<string>()
mapkeys.addAll(mapname.keyset());
string query=’Select id from lead where fieldName IN:mapkeys’