WP query – WP_Query, ACF field and table

First of all, sorry this title, I really do not know how to title the question without writing a blob text! 🙂

Anyway, my problem is this: I have a custom message "Risorse" (en: Resources). It only supports titles. All other parameters are custom fields created with ACF. One of them is a relationship in which I can select one or more pages.
So, for example, I can create a resource and select a two-page relationship. In DB, it is registered in this way

a: 2: {i: 0; s: 3: "727"; i: 1; s: 3: "729";

Now, when I load for example page 727, I want to list all the resources related to this page.

I'm trying a custom query but I do not know how to set the meta_query array. I have tried something like:

& # 39; meta_query & # 39; => array (
board (
& # 39; key & # 39; => & # 39 ;, product
& # 39; value & # 39; => Get_the_id (),
& # 39; compare & # 39; => IN & # 39;
)
)

Obviously, no article is returned because the meta_key "product" contains an array of values.
How can I get all the resources that have a relationship with a specific position?