With a NEET score of 630 and an All India Rank (AIR) of 45,387 in the General EWS category, finding an MBBS seat will largely depend on the cutoffs for different colleges. Based on previous trends, here's an approximate idea of where you might secure a seat:

1. Government Medical Colleges: You might have a chance in some lower-ranked government medical colleges, especially those in states with relatively lower cutoffs. States like Bihar, Uttar Pradesh, or even some northeastern states could be options.

2. Private Medical Colleges: You might also have a chance in private medical colleges, which often have slightly lower cutoffs compared to government colleges.

3. Deemed-to-be Universities: Some deemed-to-be universities might offer admission based on your score, though fees and other factors should be considered.

To get specific details, you should check the latest cutoff trends for NEET 2024 for different colleges and states or consult the NEET counseling authorities.