mysql query gets slower with increasing page number
when you're using the "limit 48 offset 7776" mysql need to scan all rows(48+7776), along with offset number increase, mysql need to scan more and more rows for "Next page"
To improve this, try:

select ... from ... where id &gt; 7776 limit 48


or try:

select ... from ... where id between 7776 and 7824