SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5d7ba3830695176ea4d5f93580d325116c7c88aa63ed34f769557db1eb6d4e6' 
  AND token = '4R+fvKSGrke4ivFQtaj3k9bK6Ta43F8jvB30lN/caZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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