SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ab444313df85eecc2f7fe367e5017dd79e227977e8682c0e2364ed70fa0c2df' 
  AND token = 'OOavXL7IMcjej5Dsn2jbLrVCnDAtvzj2LqWecXEhEpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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