SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a502615564f070bbcda9e8be3caa09c2a5f6a13f2ccd5790eac439e2037f10b0' 
  AND token = '0d+NzrMm0rhijPzQMOLufu+Lfn/2mRotWAFy5+IoaMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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