SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e16c84f863a688f29536c0ab687a560a4a2820b9cb63b73a2b32d5ade5173543' 
  AND token = 'OkGQD4ttSrOZga3E2sPzgMFpmgea29oZSnwjn0LwGDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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