SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '686561a181fef8c256a59ed82a0aacbc1023e640c19458e90d8c413678951a22' 
  AND token = 'XVFqVBKGRzbOoUJY/vuvhy9QrM8EpBfC6/0ApTj2nfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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