SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bbd83f57c0d51636c91d71ae5358842ed5f25c86e65c5fb832e7c790bfaabbe' 
  AND token = 'D0WFceRyWnSOaCXN8jXqTBEbwXeS9IspAJg1432V5Zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}