SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2319cf98b59349c2880040fe49d7830a18a917d3f5405cdf6753635305b7c87c' 
  AND token = '0Lwufcy5inbf3NzOeqm1JrjVXH+V4Wh8vZWpUt0OBmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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