SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '162d2337f448a70a816b92864b942a9fd5c92f9274c0be347cecb3b43d27f447' 
  AND token = 'tkW+zKM0hxgssBTo3qstTf+O65KJhdHsew41nEqj1Bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00766

JSON explain

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