First advice: you can speed up query by applying index to columns in where clause, i.e.
Second advice: indexes slow down deletion and insertion of rows in a table, so if you abused indexes (and defined many on one table), deletion also may be slowed down by these.
Generally, there is no obvious answer:
delete ... where can be thought as steps:
Find rows to delete - it can benefit from indexes
Delete found rows - this suffer from indexes
So you can benchamrk, which step is more important to your query.
For reference: More indexes, slower DELETE, there you can read:
In theory, we would expect the best delete performance for a table without any indexes—as it is for insert. If there is no index, however, the database must read the full table to find the rows to be deleted.