Check if WP page is unused

Go to Theme Options -> URL Config -> Price plans (field).

In Price plans input field, you'll see the pricing plan URL.

Compare the Pricing plans input field value with the permalink of the pricing plans (Select Your Plan) pages.

If the permalink doesn't match with the value in the Pricing plans input field then you can delete the page.

Note: Double check first if there's anywhere on the site that is using the page before deleting it.