SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af733b5e2c98e2dc33580ee5b3ccbbe31cf17aa9b5d89df9bfb1eb8def56d819' 
  AND token = 'YRiIpWUYhfRKjjvk8UoyYVGr7jkHiGZBWzPiErJ/oPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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