Allow only Admin role to access plugin settings/options page

The 3rd argument of add_options_page is the capability required for this page to be displayed to the user.

Then to allow only admin to use this page, you have to set a capability which is only owned by admin, like activate_plugins.

So change read to activate_plugins like this:

add_options_page( 'MyPlugin Options', 'MyPlugin Options', 'activate_plugins', 'myplugin-options', 'myplugin_options' );