SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db8a5cc3fc4970ef9916cae073b2281c6c54ba3525a49ca12bb19f495fb49b94' 
  AND token = 'jOrOb1F3szHNrSuiDUhJbqKmWnnnZQlSqdU/XHrEAHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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