SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd900d0741254207adf3d52fa5219000d8020ef2ac42bfd71ef347082f747fad1' 
  AND token = '6rqKvBNXPH+Sv3QYgWLhny/SGBjA9W76LSPrNOiB+rE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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