Find specific query in Query Store
One way to do this is to query the Query Store views directly for the info you've gained from the plan cache:

SELECT 
    qsq.query_id,
    qsq.last_execution_time,
    qsqt.query_sql_text
FROM sys.query_store_query qsq
    INNER JOIN sys.query_store_query_text qsqt
        ON qsq.query_text_id = qsqt.query_text_id
WHERE
    qsqt.query_sql_text LIKE '%your query text%';


The sys.query_store_query table also has some of the other fields (query_hash, last_compile_batch_sql_handle, statement_sql_handle, etc), which might find the query you're looking for more reliably.

Basically the point of that is to find the "query id" in Query Store, as you'll need that to find plans for it and force one.

Once you have the query_id in hand, you can go to the UI in SSMS and find the query using the "Tracked Queries" node:



From there you can click on the plan you want, and click "Force Plan" to force it: