Slow queries on indexed columns (large datasets)
I would try using UNION except for OR condition.
You could try:

( select p.EAN13, p.company_tk, a.attribute_type, a.val_t, t.title, t.field_name, t.seq from product_base p
inner join attribute a on p.EAN13=a.EAN13 
inner join attribute_type t on a.attribute_type=t.attribute_type 
where p.EAN13=705632109762 and a.attribute_type=1 )
union all
( select p.EAN13, p.company_tk, a.attribute_type, a.val_t, t.title, t.field_name, t.seq from product_base p
inner join attribute a on p.EAN13=a.EAN13 
inner join attribute_type t on a.attribute_type=t.attribute_type 
where p.EAN13=705632109762 and a.attribute_type=3 )
order by 7;


Maybe MySQL optimizer will choose better execution plan.