SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ed15cf5315f09f66dca84d483b8e82c6d7601091e483f50d8cc89a76b3fb390' 
  AND token = 'h2TgltXJKgYk8tNmfFJsrC/xxUqBFnmTo80oOwoIIPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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