How can I model a column in Cassandra (Datastax version)?

I'm working with Cassandra (Datastax version) and I have an issue. I want to model a column which is (always) going to change. I can't just create a column family with 1,2,3,4..10 columns because tomorrow probably can change.

I think in collections, but I got to query into these. I need query into this information every second.

Ex: With map:

<'col1':'val1','col2':'val2'> 

I need to query like this:

SELECT * FROM example WHERE 'col1' = 'val1' AND 'col2' = 'val2';

I don't know how to do this and this is extremely necessary for what I want to do.

I read that you can create a column (text) and implement a kind of format:

colum1 = 'val1\x01val2\x01'

But this doesn't resolve what I want to do, because I can't query in these fields (or don't know how)

How can I model something like that?

I can't use a collection because (according to what I read) it is slow.