documentclass{scrbook}
KOMAoptions{paper=156mm:234mm, BCOR=8mm,twoside,
    headinclude=false, footinclude=false,
    headings=normal,
    chapterentrydots=false,  % default
    sectionentrydot=false,
    }

begin{document}

tableofcontents

chapter{one}
section{oneone}
end{document}

RedeclareSectionCommand[
  toclinefill=hfill
]{section}

documentclass{scrbook}
KOMAoptions{paper=156mm:234mm, BCOR=8mm,twoside,
    headinclude=false, footinclude=false,
    headings=normal,
    chapterentrydots=false,  % default
    }
RedeclareSectionCommand[
  toclinefill=hfill
]{section}

begin{document}
tableofcontents
chapter{one}
section{oneone}
end{document}

RedeclareSectionCommands[
  toclinefill=hfill
]{section,subsection}