SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '621b81292e83a7b1a9ae8fda5f834a118905835a21af321e03b64315905e6aee' 
  AND token = 'bINXyzsoAHBxnxm+Ev+IUeXHnwccjofhNdHoweLfYsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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