SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89536bd349569842eb3cfa00dbae76f9bbd0e525f532114c3ea7d483e297ad06' 
  AND token = 'E2ejJ8/PKGBVizai9LJOGYXzt81DmyNZTTFTpU4UdU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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