SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '599b6789c96f37469a265d341ffdbb0098702243166a8bf563087d24e7efdcaa' 
  AND token = 'K22N05NPf43WQUbjo+2HfUmsT+z4lB7MiTLhEGZrcQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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