SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fad49d67b7cfe976e04b1bd4a1afebeb89f399860a7fba8a20cb26a008a9a2d5' 
  AND token = 'Bq4xArdcyzj+mYA4DjnheOJQ36vCcW/ZZXb/pqmwN3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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