SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af33427d54213180fbe218c54531cb068d9ee53df429f93f82f7d1ae86d74267' 
  AND token = 'tAVcHndCbplo4lT9W5yzBBV55FG2KhuCb+P1h2+ZtPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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