SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1851bf548069bbd413fff5bfb6d3610b840b56bec1c26b0b7ea18e4584633a99' 
  AND token = 'BfJ4KtgUIJmLq9GpWDjgWrPySY2MsIO3+V5Lhfv4ydM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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