SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2098e09e120f96d2b3e0daf673d4be1010a8ce4358e001dbbee5c4ad6511ce25' 
  AND token = 'nIzMjPWjRs78gExGuSTpQUR+evnWLluUefBdU0xBKCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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