Script Localization doesn’t work

Copying from the answer here regarding variable scope

Variables inside a function are only available inside that function. 
Variables outside of functions are available anywhere outside of functions, 
but not inside any function.

Because of that, you need to add your $translations array within the kvkoolitus_load_comment_validation function, like

function kvkoolitus_load_comment_validation(){
  $translations = array(
    'value1'  =>'This is first value',
    'value2'  =>'This is second value'
  ); 
  wp_enqueue_script( 'simple-js', plugin_dir_url( __FILE__ ) . 'js/jquery.simple.js', array('jquery'), '', true );
  wp_localize_script( 'simple-js', 'translations', $translations );
}

add_action( 'wp_enqueue_scripts', 'kvkoolitus_load_comment_validation' );