SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76ae2711305c7b9c186a87265e5228a8d9f1bbfe8f64fde6fd9bd92297a9df31' 
  AND token = 'HZelqpKvBjDnHACaD+FlinlDHjxqsoY7yRK4M0ssDZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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