SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30f19326e776dff438b5fd1f06258399feeb8a87d1e52175e8d2240b9cb1c412' 
  AND token = 'SKPv4xCzJI5TSPIqoln0ubB0t7hVR+7AgMHYOpKNrCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}