SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f4cc587298f7c5c540740602739f58110b8f2330c50b5b820d8d7486865c94f' 
  AND token = 'QGRtnOMBaCVaeZnzn/sSLtfUWi1+WzTGFPnhVbgmRyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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