SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '549b6718e1b724c38d39612d1b580bff1d6f478c1ab394f2d6b41a8c3697f4fa' 
  AND token = 'tzlZa+nLUDw1XSydJqe5aiMjcOR5sg79q0sI8nSBBgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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