SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c0f7cbadd01965da7e2f01916a6ba013fcf2df1193600e2edbf86de33cb73c37' 
  AND token = '78WSPrCxyEWw/Y02OaizN2LsxCfZzvBAYCVeLnF9YDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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