SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18ac965d4097c8c47ad0eee6f87157507f086996f878566132bb531c37a144c8' 
  AND token = 'CZouamTmVjbUmqrUUA86qmYaFN/bnfI89Z5EbdeTRls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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