TOUCHCount how many of the given keys exist.
| Syntax | TOUCH key [key ...] |
| Group | generic |
| Arity | -2 |
| Since | 1.0.0 |
| Flags | readonly |
| Complexity | O(N) keys — one existence probe per key on its owning shard |
| Redis compatibility | differs: kevy has no idle-time clock to reset, so TOUCH is EXISTS with the eviction bookkeeping the probe already does |