  The X-ray satellite XMM-Newton has so far revealed coronal cycles in seven
solar-like stars. In this sample, the youngest stars $\epsilon$ Eridani (400
Myr) and $\iota$ Horologii (600 Myr) display the shortest X-ray cycles and the
smallest cycle amplitudes. The corona of $\epsilon$ Eridani was modelled in
terms of solar magnetic structures (active regions, cores of active regions and
flares) at varying filling factors. The study revealed that 65-95% of its
corona is covered with magnetic structures, and this was held responsible for
the low X-ray cycle amplitude. It was also hypothesized that the basal surface
coverage with magnetic structures may be higher on the corona of younger
solar-like stars. To investigate this hypothesis, we study the solar-like star
Kepler-63 in the X-rays. With an age of 210 Myr and a photospheric cycle of
1.27 yr, it is so far the youngest star observed in X-rays with the aim of
revealing a coronal cycle. In the long-term X-ray lightcurve we do not reveal a
periodic variation of the X-ray luminosity, but a factor two change would be
possible. As for the case of $\epsilon$ Eridani, we modelled the corona of
Kepler-63 with magnetic structures observed on the Sun. The study suggests that
100% of the corona is composed of cores and flares of Class M, justifying the
absence of an X-ray cycle and confirming the analogous results derived for
$\epsilon$ Eridani. Finally, we establish an empirical relation between the
cycle amplitude and the X-ray surface flux . From the absence of a coronal
cycle in Kepler-63 we infer that stars with higher X-ray flux than Kepler-63
must host a significant fraction of higher-energetic flares than those
necessary to model the corona of Kepler-63. Our study opens new ground for
studies of the solar-stellar analogy and the joint exploration of resolved and
unresolved variability in stellar X-ray lightcurves.
