SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '659f739fbf55e697a81b5471bf8587226407f81b7747f51c11afa599e45ac854' 
  AND token = 'Kam2TLJo9Yz5i3bwcD4cJVbG+IqtCguDZkAlU25uHB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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