SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ff41a40ebe5ea358da7102ef3ed5ddcf6c1671b6d5f0bca64a5d37582463287' 
  AND token = 'KeMFTsfEok9LPoEEZUrZP7QTvNHhF6eRjW5jUnn9VuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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