SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54ea53462335b1a15e7f08e848c0d13cccb32424b3d9214ceadbc72a515aa08e' 
  AND token = 'cvbtaDNq9DlttQJEG0/X5lxh1Kr5Mzcnh1TxcIBiq7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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