SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29f142c9e10c5ac8c2c38f436132c700744fec924b934090c8a653ee0aa87e89' 
  AND token = '2T8HG/0hqj8p3TnE4BUBwXd5vz9UjhlrzjcJyt1ze4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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