  MAXI J1820+070 is a newly discovered transient black hole X-ray binary, which
showed several spectral and temporal features. In this work, we analyse the
broadband X-ray spectra from all three simultaneously observing X-ray
instruments onboard AstroSat, as well as contemporaneous X-ray spectra from
NuSTAR, observed during the hard state of MAXI J1820+070 in March 2018.
Implementing a combination of multi-colour disc model, relativistic blurred
reflection model relxilllpCp and a distant reflection in the form of xillverCp,
we achieve reasonable and consistent fits for AstroSat and NuSTAR spectra. The
best-fit model suggests a low temperature disc ($kT_{\rm in} \sim 0.3$ keV),
iron overabundance ($A_{\rm Fe} \sim 4-5$ solar), a short lamp-post corona
height ($h \lesssim 8 R_{\rm g}$), and a high corona temperature ($kT_{\rm e}
\sim 115-150$ keV). Addition of a second Comptonisation component leads to a
significantly better fit, with the $kT_{\rm e}$ of the second Comptonisation
component being $\sim 14-18$ keV. Our results from independent observations
with two different satellites in a similar source state indicate an
inhomogeneous corona, with decreasing temperature attributed to increasing
height. Besides, utilising the broader energy coverage of AstroSat, we estimate
the black hole mass to be $6.7-13.9 \ M_{\odot}$, consistent with independent
measurements reported in the literature.
