Order of search results for exact match content
Database search doesn't support phrases searches as stated here by the maintainer of the module (cf. https://www.drupal.org/node/2043339#comment-7654017) :


  Are you using the Database Search backend? In this case it's clear, because that backend currently doesn't support phrase searches due to technical restrictions.
  However, results should always contain both words, though not necessarily next to each other.


In order to sort your results, see this related question/answer I have no fields available for sorting with Search API sorts module