troubled, worried, distressed
惸 centers on a state of inner distress: being troubled, worried, or emotionally distressed.
惸 combines the heart radical 忄 with 㝁, which likely contributes the sound. The exact historical development of 㝁 is uncertain, but the character as a whole expresses a troubled heart.
The heart radical 忄 beside the complex 㝁 suggests a heart tangled in worry. Picture your heart caught in a web of distress.
For ケイ, imagine a worried person holding a heavy key, their heart troubled by the weight: key -> ケイ, and the heart 忄 is distressed.