SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6c6651bc781bd2ae45d31cd31f594c6b7fedf78d12400a16324c82f1eb924a2' 
  AND token = 'b8zlsuTmkCSQhOfsmNLUU9nNdvIkvEoZeDJukDT33ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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