While the Ivy schools are the top feeder for MBB firms, it is certainly feasible to come in from non-target schools.
If you are still in school, it would be highly advisable to polish your resume by inviolving yourself in a broad range of experiences, getting several achivements in the process (academic, extracurricular, international exposure) while also forming skillsets in specific industries and functions which are in-demand (can also be in a niche territory).
These will enable you to compete with the profiles of Ivy school graduates.
To further your chances, diligently get in touch with current consultants (esepcially partners) int he Firm, as much as you can, as their referrals, would enable a higher chance to get pass the initial CV screening.
From there, your performance in case interview takes the priority for the consideration.
Hope it helps.