Maybe 1 min: 1st and second words by inspection, 3rd word by letter pattern off to the races.
About 2 min. You’re right, third word was key for me.
I don’t know how you get the first two words by “inspection”, but the third word is obvious. Once you have that, the first words aren’t hard, and once you fill in the first two letters of the second word, the first word - and the entire puzzle - is no challenge.
BTW, some words that fit the pattern of the third word are:
ADLAND
ADWARD
AERAGE
AERATE
ARTAIR
ASIANS
ASKARS
BALBOA
BRIBER
CANCHA
CERCLE
CONCHO
CONCIO
CSECTS
DEIDRE
EDMEAD
EMBEAM
ESKERS
ESTERS
GAMGIA
GANGSA
GANGWA
GILGAI
GLAGOL
GORGIO
GRAGER
GREGOR
INDIAN
INDIGN
ITOIST
KECKLE
LAELIA
LESLIE
LEZLIE
MNEMON
NARNIA
OACOMA
OCTOIC
OLEOYL
OSMOLS
OSMOUS
PEOPLE
PILPAI
PROPER
REDROE
RETRUE
REURGE
TANTRA
TEATHE
TENTIE
TESTAE
THATCH
THETCH
TOSTAO
TRITER
TRITOR
UNBURN
UNTURN
USQUES
Only one commonly shows up in cryptograms.