The most common and most likely answer to this crossword clue is the 7 letter word INTENSE
I've seen this crossword clue in Financial Times
I
N
T
E
N
S
E
More clues leading to the result INTENSE
- Concentrated at home on future perhaps
- Strong set with nine changes
- Stated where one sees circus performers of extreme strength
- Violent in future, perhaps
- Strong under pressure, leader’s elected
- Strong batting, perfect for example
- Concentrated where refugees may be housed, they say
- Earnest European getting behind how metric system counts
- Trendy future may be full on
- Home may be perfect and strong
Buddy explains!

The straight part
We know that "Keen" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case keen = intense.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INTENSE mean?
INTENSE adjective- Strained; tightly drawn.
- Strict, very close or earnest.
- Extreme in degree; excessive.
- Extreme in size or strength.
- Stressful and tiring.
- Very severe.
- Very emotional or passionate.