SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce6a6468b145346e9a8946c5186411a75a0b484e157127ff0b07048598e3e9c3' 
  AND token = 'EzrqWMjvQTvb2esSAjK2c2mtc70711P7xiv9OMK7TeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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