SELECT 
  1 
FROM 
  vi_lock_keys 
WHERE 
  key_id = '9b446a5f6d35c3b4d7c6814deac35e32c002a5ea8d0c37cd04af49520d27f65e' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}