SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4665ceda56ee2884d88dec5f54b4404fdb0f75eb1a05e09c789613e1ce874bc1' 
  AND token = '0fv9qe0Zo7PEhCkiTVTb0g4lVawV5a9LXtRzkFHCvEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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