SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2cb5ef15819da4a4991a501f06826bacb2ab400ffcf7bc7cf1cb59291b74601' 
  AND token = 'zcVspLXDnl5vszzGjT6UIIJRnCxHVu6yHcVwMEXOx3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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