SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84d85e6d32d991ae48c4e2ea2d0ea6ee9fbbe41ba570b0c985b12429e1b0680d' 
  AND token = 'w4zqUTTwFxJcWiMAyQDMH7mcJbJnmXU5iSbZ4RwKWSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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