SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2f406ad598ac8c5df1f7e79be71a725ddf4529cf747b1e65740ff63b11a3d808' 
  AND token = 'ljcszwryY+pmKZDTz6v7hpfCqScbjvc7zSpRdXypOFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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