Check for valid key

Also any option to see license activations in admin dashboard

Using the www.ads-software.com version no. But with our paid extension yes (here), it comes with manage pages to view and edit customer license keys from the admin dashboard.

is there a way to check license key if it’s valid or not? I mean the key which is not activated yet, just to see if the entered value is a valid key or not.

With the api no, since the activation endpoint already does the process and there is not need to do a previous request just to validate.

But if you wish to do this, you can accomplish this by using the LicenseKey model class:

<?php
use LicenseKeys\Models\LicenseKey;

if ( LicenseKey::find( '[a-customer-license-key]' ) ) {
    // FOUND
} else {
    // NOT FOUND
}

a query to db for retrieving that information with a custom plugin?

You can always use the model explained above to query the db, the model uses the FindTrait.php, which you can review, to provided proven query functionlity.

An example:

<?php
use LicenseKeys\Models\LicenseKey;

$license_keys = LicenseKey::fromOrder( $order_id );

If you wish to extend the query functionality to add custom queries you can do this bu creating you own model that extends from the existing one:

<?php
use WPMVC\MVC\Collection;
use LicenseKeys\Models\LicenseKey as Model;

class MyLicenseKey extends Model
{
    public static function all()
    {
        $license_keys = new Collection;
        // TODO QUERY CODE
        return $license_keys;
    }
}