SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78098cd7d46d1524d150551b541e9749ab19989c1fc38569bae67b842204876e' 
  AND token = 'YfkkyxSO7vh++91zyjI/WtOvSD/fmYq997UgjokDuPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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