I am currently retrieving all pages and filtering out ones that are not published in the code, checking whether DateTime.Now is smaller than this:
static readonly DateTime IMMEDIATE_PUBLISH = new DateTime(1900, 1, 1);
public static DateTime PublicationDate(this SPListItem item)
{
    // get start publish date
    PublishingPage page = item.Publishing();
    if (page != null)
    {
        bool isPublished = (page.ListItem.File != null)
            ? (page.ListItem.File.Level == SPFileLevel.Published)
            : true;
        bool isApproved = (page.ListItem.ModerationInformation != null)
            ? (page.ListItem.ModerationInformation.Status == SPModerationStatusType.Approved)
            : true;
        if (isPublished && isApproved && (DateTime.Now < page.EndDate))
        {
            return page.StartDate == IMMEDIATE_PUBLISH ? page.CreatedDate : page.StartDate;
        }
        return DateTime.MaxValue;
    }
    // not a scheduled item. treat as published
    return DateTime.MinValue;
}
What would be the equivalent CAML query, so that I SharePoint doesn't pull unnecessary items from the database?