SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '42d776c54a74e3eb07a8b1168e8b79c3fe54bf696ab633b2b0738fac19d1c43f' 
  AND token = 'nYYwpj+DcShGue+YKkezs/+IV6wBqt0GFDNAbHuwsEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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