Laravel Duplication Of data

I am working on a laravel project were when submitting a form, I am getting a value from a column name x and incrementing it by 1 and submitting,

It works fine, but on production when I open two browsers and submit both forms at a time - it gets duplicated, I have also added a validation to check the unique data

but it won't work if I submit multiple forms at a time

I am not that much expert in laravel - do I need to look on Pessimistic Locking ??

Can someone give me a suggestion?

via Chebli Mohamed