SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a9c98da6cc37a51470ed63c48f3eea9a6bc285eee6ce348a3a65e9f72396ef69' 
  AND token = 'QJFpgO5HiASJdhRsuYe4QvGZ2P/WNhdOtC0inHK7OM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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