SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '828989524bec9994d71d8b402ec5bec62a74e2fb44efe12c1af2a2435c5f1e13' 
  AND token = 'KuecNwF8nYWfJnSIlJHsj/ul0nE3MxyfLRJ+Wi+vt38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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