SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1164dea55d57bbb0e725424c21d4fa8f1d439a39e97f98c886c11984a487da37' 
  AND token = '0ncmGONVj5khUrHzyXFlhxBwyV2NEbsWQBYqatSij48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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