SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ceb47ec25ba045cec8880deee68f5efa367c57f5c545096ec6016a5fb4b4e0c' 
  AND token = 'LEr1ZWt+mk/xSr6/UCk3hAmLwuVUwyzxVVcyZ73lar8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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