Actual time and highlighting cells

Using Google Sheets I've created a schedule and I'd like to highlight a cell whenever a specific time applies.

https://docs.google.com/spreadsheets/d/1Onw2ORGB5j8s4l5VmdJp354NJWcqGOV-AzWryoGrFq0/edit#gid=639195395

For example:

Cell B12 shows the actual GMT +1 time with the formula: =NOW(). Right now it's 5:25 pm. So, the cell A32 should be highlighted as cell A32 contains 5 to 6, written as a text. Whenever the hour runs to an end, the next cell, A33 (6 to 7 pm) should be highlighted, as it would be 6:00 pm @ Cell B12.

Can someone guide me a bit as I'm a bit confused what to do.