SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8818fd791c8123f9d9906bcc30f760a876b4b5f469c753bed2c155a8457b008a' 
  AND token = 'BdhAHS4xCEBTtfsSnVKuRPw71gkgqmR3JPCUU89N7NU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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