SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b56648665c4e5dd04299589f63aa7d54a6a36dd550167b969767b054026c9fe' 
  AND token = 'JeHaTKH3uNIB+AwMjT7YnDNOmWvmwGjgLtT8IlN/E2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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