How to improve performance for read only innodb MySQL Database
Can't optimize it without some serious surgery.  Think of it as a "bounding box" as discussed in http://mysql.rjweb.org/doc.php/find_nearest_in_mysql

It discusses 5 ways of doing "find nearest".  You are on the second-worst, and probably do not have the best indexes for that.  Then it moves on to 3 faster ways to run the query, but they require non-trivial effort.  But the speedup is quite significant.

As for concurrency, those algorithms provide performance by decreasing the I/O and CPU.  This allows for more concurrency and even lower CPU usage.