PostgreSQL get all records with most recent date

I have this query that will run on very large data sets and it is too slow.

SELECT *
FROM tableA
WHERE columnA =
        (SELECT MAX(columnA) -- select most recent date from entries we care about
            FROM tableA
            WHERE columnB = '1234' )
    AND columnC in (1,2,3) -- pull a subset out of those entries, this set here can be a thousand (ish) large. 

table A looks something like this

pk	columnA	columnB	columnC
1	5/6/2022	1234	1
2	5/6/2022	1234	2
3	5/5/2022	0000	3
4	5/3/2022	0000	4

There are about 1000 distinct entries in columnB and many orders of magnitude more in the table. Is there a better way to structure the query? Or columns I can add to the table that will make it faster?

Answer

I suspect that it will be the last line which is taking the most time because the list must be parsed.

AND columnC in (1,2,3) 
-- pull a subset out of those entries, this set here can be a thousand (ish) large. 

It would be better to put these values in a table with an index (PRIMARY KEY) so that the query only consults the index.

Join tableX X
On x.id = columnC;

We can also create indexes on columns A and B.
https://dbfiddle.uk/?rdbms=postgres_12&fiddle=6223777b7cbfa986d1eb852ac08aeaaf