SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '283c8b91ec78b4b310f6b8d4e12a8c2f708a758ed6dffd550f0866b7a97b9c26' 
  AND token = 'zwurGFHSo9l+8piUyAManToJNXCs6/ERMDnJeVhIw+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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