SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27da6cc42b993b5bf06afd2d4f0a6fac21fd21d7c1b65a33b210b56482a0da7c' 
  AND token = 'NaRq0zPSVRcbLNpQtUiinwyqz0YgjC5i4B4sZHpsSYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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