SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d0443af981ad0d789986b3785bbb612feae1f6075e933273ccd618962c646b0' 
  AND token = 'Cp+zYRucubyfUCQKGIg00r7YGCHpdKPTkRW67fpm8yg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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