SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c248149ba7d8fd3ba9a082760bc3d27a4d77d9dc917f00b5f8c5b95386f55889' 
  AND token = 'tTwV/JSg1NN0JNQTFlWMfPja0V9lENl1deKcoCmgYHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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