precedence of operators

[Jean Beaulieu]

Hi,
My database (mysql) will be quite large at some point, so I must know before which pattern in preferable. The pattern that I have right now is
SELECT * FROM TABLE WHERE (A) AND (B OR C BLABLABLA)
but I'm unsure if it's not better to use
SELECT * FROM TABLE WHERE (B OR C BLABLABLA) AND (A)

The second parenthesis (B OR C BLABLABLA) contains many statements combined with AND, OR, <>, =, etc...t's too long to give them all
The first parenthesis contains 'A', which is in reality a test inside a gap of longitudes and latitudes ( like if (table.long > longit_min AND table.long < longit_max AND table.lat < latit_max AND table.lat > latit_min)

The geolocation test would eliminate 99.8% of the records, but the bigger parenthesis at most 80% of the records, so obviously I prefer to eliminate 99.8% and after eliminate 80% of what's left.
How can I do this if I want the instructions over longitude/latitude executed first?
Is my reasonnig correct?