SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8c9db783d1fae67634d9c380e9df387d66a098628994269a7d0a56e40eb73aa4' 
  AND token = 'IhPLDvuhQ/XnUHTF+Pg6Q/b+yZEppblBol4mJ/mmOgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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