From queries and from trigger scripts and other integrations there is no way to identify if an item violates a constraint, before trying to edit it and receiving an error. For some constraints a query can be custom built to find items which don't match the given conditions, but this doesn't work for IBPL constraints based on data not local to the resulting items of the query. In scheduled scripts if an item with a previously broken constraint is edited, it throws an error. Since a delta bean is then open with a violated constraint, it will continue to throw the same error until it's corrected. All of these problems could be solved if there were some condition on each item accessible by query and issue bean to indicate that a constraint is violated.
I'll also note that finding a pre-existing constraint violation on an item does not always require that a new constraint be put in place after the edit. So it's not just a problem in configurations which are still under development.
I could imagine that a query condition to check whether constraints are violated would take a long time to resolve and would not be recommended for a commonly used query, but as it is there's not really a good way to find these items.