MySQL query runs ok in phpadmin but hangs in php

I have a fairly simple query which runs okay when I test it in phpMyAdmin:

   SELECT   
        c.customers_id,
        c.customers_cid,
        c.customers_gender,
        c.customers_firstname,
        c.customers_lastname,
        c.customers_email_address,
        c.customers_telephone,
        c.customers_date_added,
        ab.entry_company,
        ab.entry_street_address,
        ab.entry_postcode, 
        ab.entry_city,
        COUNT(o.customers_id) AS orders_number,
        SUM(ot.value) AS totalvalue, 
        mb.bonus_points
   FROM     
        orders AS o,
        orders_total AS ot,
        customers AS c, 
        address_book AS ab, 
        module_bonus AS mb
   WHERE 
        c.customers_id = o.customers_id 
        AND c.customers_default_address_id = ab.address_book_id 
        AND c.customers_id = mb.customers_id    
        AND o.orders_id = ot.orders_id 
        AND ot.class = 'ot_subtotal'    
 **  AND c.customers_gender  = 'm' AND c.customers_lastname LIKE 'Famlex'
    GROUP BY o.customers_id

The row marked with ** changes depending on filtering settings of the application making the query.

Now, when I test this in phpMyAdmin, the query takes a couple of seconds to run (which is fine, since there are thousands of entries and, as far as I know, when using COUNTs and SUMs indexes don't help) and the results are perfect, but when I run the exact same query in PHP (echoed before running), the MySQL thread loads a core to 100% and doesn't stop until I kill it.

If I strip the extra stuff to calculate the COUNT and SUM, the query finishes but the results are useless to me.

EXPLAIN:

1   SIMPLE  mb  ALL     NULL                        NULL        NULL        NULL                                48713       Using temporary; Using filesort
1   SIMPLE  ot  ALL     idx_orders_total_orders_id  NULL        NULL        NULL                                811725      Using where
1   SIMPLE  o   eq_ref  PRIMARY                     PRIMARY     4           db.ot.orders_id                     1           Using where
1   SIMPLE  c   eq_ref  PRIMARY                     PRIMARY     4           db.o.customers_id                   1           Using where
1   SIMPLE  ab  eq_ref  PRIMARY                     PRIMARY     4           db.c.customers_default_address_id   1

EXPLAIN after applying indexes and using joins:

1   SIMPLE  c   ref     PRIMARY,search_str_idx              search_str_idx          98      const                                   1       Using where; Using temporary; Using filesort
1   SIMPLE  mb  ALL     NULL                                NULL                    NULL    NULL                                    48713   Using where
1   SIMPLE  ab  eq_ref  PRIMARY                             PRIMARY                 4       db.c.customers_default_address_id       1    
1   SIMPLE  ot  ref     idx_orders_total_orders_id,class    class                   98      const                                   157004  Using where
1   SIMPLE  o   eq_ref  PRIMARY                             PRIMARY                 4       db.ot.orders_id                         1       Using where