SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '046458b0a107e052ddd075c1906351a3784b7cfe5a0ef57de59732b01b016db5' 
  AND token = 'gFhviVxv4mj+Qjg+Cq9+m2rdUDI3AjwWzy26wqv18G8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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