SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89e876d407072d40173c6a6380219dabcd4509702f247979905e0d27c9d8dd7e' 
  AND token = 'uJ2CKAmjZd39VlWRWgNzkCRSZ7S22RadAqpPbPRnlyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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