# Pastebin EjXQ78yK
# This awk program

BEGIN { FS = " *= *"; in_section = 0 }
/^\[.*\]/ { in_section = 0 }
/^\[aws_profile\]/ { in_section = 1 }
/^aws_access_key_id/ && in_section { print $2 }

# Against this input

[no]
aws_access_key_id = wrong key

[aws_profile]
aws_access_key_id = right key

[also no]
aws_access_key_id = wrong key

# Prints

right key