SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f6edcbc603a12707a9ad4b82e74f480c1626b23e27f4db2155be32315f31c66' 
  AND token = 'wGWttqYddDj+aLyNh3QNSe/2TNieCZuVXo3H6CvYgjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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