I need to refactor system, where students are watching slides, lectures and doing tests, where their knowledge is being check.

My trouble is how to track progress of my students.

1. Have single mySQL table for user progress, where I will have JSON field with saved progress of users (seen slides, lectures, tests progress)
2. Have separate tables for slides_progress, where each seen slide will be saved in “seen_slides” table (id, user_id, slide_id)

I think second approach is generally better, but I have problem with application scale. According to my calculations, there may be 500 000 000 entries in table after ~ 1 year.

Will mySQL handle so big amount of data? Will indexes still make it fast if it will be growing?
Maybe you have better approach idea?

I would like to stay with mySQL, but maybe there is some kind of DB better suited for this problem?