SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b46457c43fcac6926da19db47a5a2e3456049150836042ff619b8d29ea7a569' 
  AND token = 'ISesIpUxmWfIIgaAgLGjtaDuai6xahL49bEqEDFg7jc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00082

JSON explain

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