SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2f9e2cbfe774fdeda1232e91c63500dd11fd41c5b27a1c7f239a6487965de91' 
  AND token = 'AVLeII53bp3uaUx3r+F9e2KXeL+b08QsJzsCt7IvDpc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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