SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75bbc43656aaac67570a14179c280b774a00ca7fb661a5cfaf7474a18f8a657a' 
  AND token = 'Y94Ypqu8x7TxBgcdGqVpwoSpBxEjeuAq8OVZMUGGPto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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