What is the best way to filter data?

Question

MySQL

There is a news feed, new ones are added every day. A person comes in and reads, we save the news he read to the database.
Question: how, in this case, is it more efficient and more correct to filter the news by "read / not read". Now each read news is recorded in the database, and the unread ones are selected like this:

select * from news where id not in (select id from viewed)

There is a lot of news, there are also a lot of viewed news. Is this approach bad or is everything ok? Base on MySQL.

Answer 1

UPDATE TABLE usersSettings SET lastViewed=NOW() WHERE userID = ...;
SELECT * FROM news WHERE newsTime > (SELECT lastViewed FROM usersSettings WHERE userID = ...) ;
Maybe something like this.

Answer 2

"a lot" is how much? If we are not talking about millions, then it will go.