These seats are called infield boxes. I have sat here a number of times, most recently, for a Padres-Cardinals game last season. Our seats were in row H. The rows are D thru K and 1 thru 18 which is the second part of section 142.
Section 141 which is to your right is a great spot for autographs down the first base line. These were ideal seats when Pujols was still with the Cardinals, we have lots of closeup photos of him.

Seats are fairly affordable as well. Paid $120 for two tickets. For Chicago Cubs games, expect to pay double that.