Problem with parser

Hi guys,
I have a problem that I can't solve right now, I'm using the parser library, and i need it to show a defined variable stored in the database in the view.

PHP Code:

$data = [
  'site_name' => $ConfigurationSite->name,
  'seo_title' => $ConfigurationSite->title,
  'seo_book_title' => $SeoBooks->title
]; 


I have this stored in the database: "Buy on {site_name}" that I save it to seo_book_title

View: 

Code:

<meta property="og:description" content="{seo_book_title}" />

And the result is:  "Buy on {site_name}" when the name defined above should appear on site_name.

Sorry about my English, I'm Spanish.
I hope you can help me, thank you and a greeting.