SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76063b49c2d8cc3dd491df8905fba0ad666262a13cd5267e2ab05faf526431ee' 
  AND token = 'zkt2NnZNHwcqWLSFDzYtv1NfDKq1CvZQDKYJZEWwbyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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