SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '883687ad432d5ecd210a98b81d0ce57b75c84fbcd707d16740045b9a1e5b46ad' 
  AND token = 'AeR3evGjI31aRseewLEL76l2Psdi2ojk1zGS65dVvsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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