SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6bee78c768282c3543dc87037b34528a8dc07a5703e9947dfb7eb7945b47c045' 
  AND token = 'CAmOfxDyVm1EPmBCC+21sP6dNMHDiCuVLa+0knrwAjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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