select P.*
from Products as P
join Attribute_values as AV
on AV.ProductID = P.ID
and AV.Value = 1
and AV.AttributeID in (attr1, attr2, attr3)
group by P.*
having count(AV.ID) = 3
Ну, естественно сочетание ProductID/AttributeID в Attribute_values должно быть уникальным.