Version1:
update creature_template set speed = 0.7 + maxlevel*0.005 where rank in (0,4);
update creature_template set speed = 0.7 + maxlevel*0.01 where rank in (1,2) and entry in (select id from creature where map=0 or map=1 or map=530);
update creature_template set speed = 1 + maxlevel*0.01 where rank in (0,1,2,4) and entry in (select id from creature where map not in (0,1,530));

Version2:
update creature_template set speed = 0.75+maxlevel*0.01 where minlevel<20 and rank in (0,4);
update creature_template set speed = 1 where minlevel>19 and rank in (0,4);
update creature_template set speed = 1+maxlevel*0.05 where rank in (1,2) and where entry in (select id from creature where map=0 or map=1 or map=530);