SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ae6a1a8de64fc4de9713e43df261ffcb89fb18711126b845119d57763bbebc6' 
  AND token = 'uUSt+AoBH0XYqVPUEq3ZSv1Q9zYdEhD5LkCDlL6VLu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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