SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdf1d514453bb7eb8502ec0ac0c8daf84398292bd09f7bb817e557035ccf8652' 
  AND token = 'qCfTj3fiNYGqeBkTowqVqX36+aEEnju/P+Pgo49rGDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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