SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33f19edb2f1f368eb751cda3ee86673dfd6735b8ca7b4697cfd3fe398125e14d' 
  AND token = 'Qs0TFfDwtHW38qgVdTt5ApOmhkfWxAO1FhGHnundEZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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