SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23408bbca747249a6ad337af774bafb40fa26a09482589635d4e01c724cd76eb' 
  AND token = 'syVasj9zurjyq/gAA8b4XtDJhPyBFqZMz9C75eWgC+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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