Prism griefing query

#Takes too long to run, needs a better index
select	B.*
from    prism_actions			as	B	#Breaks
	inner join prism_actions	as	P	#Placements
		on	P.action_time	<	B.action_time	#Placed before broken
		and	P.action_type	=	'block-place'	#Placed
		and	P.player		<>	B.player		#Placed by another player
		and	P.world			=	B.world			#In same world
		and	P.x				=	B.x				#Same X coordinate
		and	P.y				=	B.y				#Same Y coordinate
		and	P.z				=	B.z				#Same Z coordinate
		and	P.block_id		=	B.block_id		#Same block type
where	B.action_time	>=	'2013-04-24'	#Breaks from date(time)
	and	B.action_type	=	'block-break'	#Breaksdelimiter