SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1bbdf86514eff9c84e36770809e64a346f2f33361abdb783088fd76bf17e83f' 
  AND token = 'POjsnIry2nUTcoc9Pj/z5PqjUxnZilsrnsuTcJROi/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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