documentclass{beamer}

usepackage[utf8]{inputenc}
usepackage[T1]{fontenc}
usepackage{lmodern}
usepackage{mathtools}
usepackage{booktabs}

begin{document}

begin{frame}{visible<1->{Test}}
  visible<2->{
  begin{table}[htbp]
    centering
    caption{Test.}
    label{tbl:1}
    begin{tabular}{l c}
      toprule
      Antal timer &
      $]0, 5]$  \ % the code causing the error
      bottomrule
    end{tabular}
  end{table}}
end{frame}

end{document}

! You can't use `eqno' in math mode.
endmathdisplay@a ...df@tag @empty else veqno
                                                  alt@tag df@tag fi ifx ...
l.24 end{frame}