SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e2f8c7c91619ccd54a730e9bec302b955bddd227ffa94c2702d56f2eb59cc05' 
  AND token = 'QnIWA/IW6qpZzr+eSTCpiLuf4oKIsf9yLPyEuTAiau0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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