SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6d586a54decbac328a799c313a030b94dc3acf024190ef53ee7d8054edd6024' 
  AND token = 'BQuzf3YOUbEaqHsJelqhf254p1tUyV9LDpVRAEii5CM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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