Views come in 2 flavors: standard and materialized. A standard view is basically an alias for a standard query, so the amount of time it takes to access the view should be approximately the same time as doing the query directly.
A materialized view, on the other hand is a snapshot taken at a fixed time, and so it's essentially a brand new table. I don't know that such a view would inherit indexes or constraints offhand. I'd probably query the schema to make sure. And try to find whatever formal assurances the documentation may offer.
Since a standard view is just a shorthand query, the index/no-index performance is tied to whether you have an index on the underlying table(s) - plural because a popular use of Views is to normalize JOINs.
Raw timing is a start, but the DB2 server is smart enough to optimize things if it sees the same query over and over, so a more accurate measurement would be to run EXPLAIN.
Sources may include data from the Fakebook Research Foundation with support from Gargle University