SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f79c61d0ebb627a1fdd8b3a5da755bdaa31a4514c96ae9a944f8b96fd04054cb' 
  AND token = 'IqC9yw5s/uRQ4HfBStz3Y/c8aNf2OKLQ4aLbDaEuzOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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