Theres no way you are gonna get 40fps on minecrat at the lowest settings at that budget with a new laptop. You have 2 Choices here.
1.- Getting an Used Laptop, I dont like this option and i wont recomend it to you. But if you are going to go with this option then i post you the safest choice for you to reach your goal.
2.- Add 100 Euros, Even 70 euros would open you alot of choices. And it would be Easy to find one for your needs.
You should be able to get between 20-35 fps in the lowest settings with optifine in the first 3 laptops, and in the last one you should be able to reach the 40fps. This is the best i can do man, its a really really tight budget.