ALKHAYR means "goodness," but has a wide range of related meanings. Al-Mawrid lists the following:

good, benefit, advantage, interest, welfare, well-being, weal, blessing, boon, benefatction, wealth, fortune, riches, opulence, affluence, etc.

In the context you presented, SABAH AL-KHAYR is a common greeting equivalent to "good morning."

KWAYYIS is a colloquial expression (mostly Egyptian), which can mean "good" or "well," sometimes used in response to "how are you?"

IZZAYYAK is an Egyptian colloquial expression for "How are you?" addressed to a male. IZZAYYIK is addressed to a female, and IZZAYYUKUM is addressed to more than one person.

Fuad

I am trying to make sense of the order of the words in your question. Here are two possibilities:

1) You may have inadvertently rearranged some of the words you heard.
Sometimes the word quways كويس is used as an off-hand response to the question "izzyak إزيك" which, as Fuad explained, means "how are you". So the sequence you heard could have been:

X> Sabah alkhayr, izzyak.
Y> quwayis.

Which is equivalent to:

X> Good morning, how are you?
y> Fine.

Of course children in Egypt are always taught that it is not courteous to repond to the question izzayak with quwayis (but they often do anyway), instead they are taught to respond with either:

alhamdulillah (praise is due to Allah)

or

Allah yissalimak (May Allah protect you from all harm).

2) Now if you are sure that you did not rearrange the words, then you may have the wrong transliteration for quayis. As Fuad explained, quwayis means good or fine. This is an adjective that you would not see as the addressee of the greeting. Instead, you normally have the person's name or title there. The nearest Arabic name to this word is `uways أويس. So the greeting may have been:

Sabah alkhayr ya `uways, izzayak?
صباح الخير يا أويس، إزيك؟

i.e. Good morning `uays, how are you?

Regards,

Alaa Zeineldine