Krishna was in moksha state, i.e. in the Turiya or the fourth state, according to this passage in Mahabharata.
Yudhisthira said, 'How wonderful is this, O thou of immeasurable
prowess, that thou art rapt in meditation! O great refuge of the
universe, is it all right with the three worlds? When thou hast, O God, withdrawn thyself (from the world), having, o bull among men, adopted the fourth state, my mind has been filled with wonder. The five life-breaths that act within the body have been controlled by thee into stillness. Thy delighted senses thou hast concentrated within thy mind. Both speech and mind, O Govinda, have been concentrated within thy understanding. All thy senses, indeed, have been withdrawn into thy soul. The hair on thy body stands erect. Thy mind and understanding are both still. Thou art as immobile now, O Madhava, as a wooden post or a stone. O illustrious God, thou art as still as the flame of a lamp burning in a place where there is no wind. Thou art as immobile as a mass of a rock......'
Mahabharata, Santi Parva, Section XLVII
A Jiva even after moksha can never become Ishvara.
Who is Ishvara? Janmadyasya yatah - "From whom is the birth,
continuation, and dissolution of the universe," - He is Ishvara - "the
Eternal, the Pure, the Ever-Free, the Almighty, the All-Knowing, the
All-Merciful, the Teacher of all teachers"; and above all, Sa Ishvarah
anirvachaniya-premasvarupah - "He the Lord is, of His own nature,
inexpressible Love." These certainly are the definitions of a Personal
God. Are there then two Gods - the "Not this, not this," the
Sat-chit-ananda, the Existence-knowledge-Bliss of the philosopher, and
this God of love of the Bhakta? No it is the same Sat-chit-ananda who
is also the God of Love, the impersonal and personal in one. It has
always to be understood that the Personal God worshipped by the Bhakta
is not separate or different from Brahman. All is Brahman, the One
without a second; only the Brahman, as unity or absolute, is too much
of an abstraction to be loved and worshipped; so the Bhakta chooses
the relative aspect of Brahman, that is Ishvara, the Supreme Ruler. To
use a simile: Brahman is as the clay or substance out of which an
infinite variety of articles are fashioned. As clay, they are all one;
but form or manifestation differentiates them. Before everyone of them
was made, they all existed potentially in the clay, and, of course,
they are identical substantially; but when formed, and so long as the
form remains, they are separate and different; the clay-mouse can
never become a clay-elephant, because, as manifestations, form alone
makes them what they are, though as unformed clay they are all one.
Ishvara is the highest manifestation of the Absolute Reality, or in
other words, the highest possible reading of the Absolute by the human
mind. Creation is eternal and so also is Ishvara........Those who
attain to that state where there is neither knower, nor knowable, nor
knowledge, where there is neither I, nor thou, nor he, where there is
neither subject, nor object, nor relation, "there, who is seen by
whom?" - such persons have gone beyond everything to "where words
cannot go nor mind", gone to where the Shrutis declare as "Not this,
not this"; but for those who cannot, or will not reach this state,
there will inevitably remain the triune vision of the one
undifferentiated Brahman as nature, soul and the interpenetrating
sustainer of both - Ishvara. .....
Complete Works of Swami Vivekananda, III, p 37-42