SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24c3668e8568a679223b9d571ad2731b4983ee5240b691c14d765da106c420cf' 
  AND token = 'LZG/zmV8eDJdOAJRHzLbuZ6qTxV7oodpWbUC1kX9pMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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