SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4990d02f402061742c4ddc98ca8b50473fd201cabaedde85d9f4fb24a55224a' 
  AND token = 'qBom04McgOFQQQqkjbPohObm+jgTcCw1aUmL2SDzi6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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