SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13e30cc54de356cbca8947e50860bcdf53d56235c4c69948e2b3ae391b6f7f4c' 
  AND token = '3GMKZl/KMMU0iCCuwCW16dsKXt32xJ/IjQKxqJ2TSHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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