SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5477bd8f5064a6476dee7d33061a991516a5b0bb3888ced744c773d1d6313722' 
  AND token = 'ZvhNWJU+/M4j1QijMUH7fg54tyaLg8b6kKnslUOkoAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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