SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ea8a75c892186d9d4d474b3e33bca7ff2f734bc7c6a5c789c91dd6f4121b922' 
  AND token = 'gBkNaMOzBbvTpG+DmWY4+JfdalaZT2zU8JzhB7ow904=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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