SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92ca69c5cc7d5799a37edb113e5bda25cd74838a5ab8c7d268fb7b8f1b645b62' 
  AND token = 'SgtKmDBgAfFAmhaDbrUgMSjfCPwnx+G7E0GwJUnX/oE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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