SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bd0d0f8cd82c2b0f1522292f467313cd90a5fb9d7f915b780cacee7855e0fa1' 
  AND token = '8A1xbD1j0bK/EBNzIlqjiT7XMjzrw29SdRnAHxTw+l0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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