The HERE and NOW is often expressed by spiritual teachers. They are referring to the ETERNAL HERE and NOW of the spiritual condition NOT the here and not of the physical life experience. There is an INNER HERE and NOW and an OUTER here and now.
In deep meditation the body is shut down so one does not experience the outer world, one experiences the INNER HERE AND NOW of the spiritual condition and state of being. When one is firmly established in the INNER HERE and NOW of the spirit one can go through life in that state and not be effected by the many changes, one remains calm, centered one sees that life is just a pattern of energy (a movie) for the benefit of the soul and its lessons and development.
When NOSTRADAMUS speaks of the ETERNAL NOW. He is referring to the INNER HERE and NOW of the eternal state of spirit-be-ing, The INNER HERE and NOW is ETERNAL, the PRIMARY NOW MOMENT OF GOD, the OUTER here and now of creation is a SECONDARY HERE AND NOW it is always changing from moment to moment. Only in a state of God-self-realization also called, Satori, Nirvana, Samadhi, The kingdom Of God, Heaven etc. etc. can one experience and understand the state and condition of the eternal now of spirit which is prior to creation, space, time and what is called infinity.
The INNER HERE and NOW is the is the PRIMARY REALITY of existence NEVER changing.
The OUTER HERE and NOW is a SECONDARY REALITY ALWAYS changing.
The first or fundamental natural reality is the HERE and NOW of God-SELF-realization.
The psychological egoic state of mind creates it's own reality, which is a "secondary" reality. It is also called hell.
The inner HERE and NOW is the spiritual state. The outer here and now is the material world and is the false condition, Jesus knew a person could not serve two conditions at the same time (two masters).