SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f436a7b3314859a136408b08c049564cb5dd5be89d06fd488fe91080ebb697e4' 
  AND token = '9gvIJMvioKBrGRha0xX3b7hRugPk29OWxvUwA0qK5vU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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