This is the 5767th most frequent Arabic word.
مازالت
"Still" or "continues to."
The word 'مازالت' is used here to indicate that the raining is continuing from the past until the present.
مازالت السماءُ تمطر.
The sky is still raining.
Here, 'مازالت' shows that the action of playing in the garden is ongoing and hasn't stopped.
مازالت الطفلةُ تلعب في الحديقة.
The child is still playing in the garden.
In this sentence, 'مازال' expresses the continuity of the action of searching for the keys.