SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '327c40604f72935c87b7ecdfbf8b65cb32f070afb31ae753e50ee03cd23fde3e' 
  AND token = 'WE8ZuKN5bvE93TXrUvVRmogDpTlqKPYTXEVPvrBmeLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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