\documentclass[a4paper,twocolumn]{article}
\usepackage{geometry}
\geometry{twoside,hmarginratio=1:1,hscale=.875,vscale=.85,vcentering,marginparwidth=20pt,marginparsep=4pt}
\usepackage{mathtools,kantlipsum}
\begin{document}
{\makeatletter
\def\align@preamble{%
&\hfil
\strut@
\setboxz@h{\@lign$\m@th\displaystyle{{}##{}}$}%
\ifmeasuring@\savefieldlength@\fi
\set@field
\hfil
\tabskip\z@skip
&\hfil\setboxz@h{\@lign$\m@th\displaystyle{{}##{}}$}%
\ifmeasuring@\savefieldlength@\fi
\set@field
\hfil
\tabskip\alignsep@