SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b9d1b093bc84317b6f6898e75f5e4c99a4438c828d16b064235bdffcfb4ecee' 
  AND token = 'DOTRCBWp0/S1RBSFtMk0fjyNP7M+eJLP246dPGdPx2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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