SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38b01a1db4c4e38995e67ae0a6d5c0a3b76530177a464599f64f2dfaf90f5875' 
  AND token = 'q9iV2iIh+2gubbTKgOFJQ3mehLKLNmiqZZ+fERkn8oc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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