SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47c7aab36da8be75b9908141119df802688b69d1c8a8237968cb9a7de59537af' 
  AND token = 'WRtdwKFPUB6PBVQA4IX54bGAKkzwZojW08BUzYdMvN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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