Select values from map with multiple key values in where clause

[Matteo Rulli]

Hello! 
I have a table like the following 

CREATE TABLE test (
    my_id uuid,
    values map<UUID, FROZEN <value_reference> >,
    PRIMARY KEY (my_id)
)...

and I would like to perform a query along these lines: 
SELECT * FROM test WHERE my_id = 670287fe-e080-42c3-9fae-7ffdc3309793 AND 
values CONTAINS KEY {00000000-0000-0000-0000-000000000001, 
00000000-0000-0000-0000-000000000002};

Is this possible?

If the answer is no, the other approach I tried is via UDF. So the second 
question is: 

Is it possible to use UDF in where clause?

Reading the https://issues.apache.org/jira/browse/CASSANDRA-8488 
<https://issues.apache.org/jira/browse/CASSANDRA-8488> issue I fear the answer 
is still no, right? 

As a last chance, I'm considering implementing a custom secondary index: is 
this a viable approach to get the kind of SELECT detailed above? 

Many thanks, 
matteo