SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'af81699b4d1fd3ad3404522eeae59cfb0d8c2029531344f1d4b81a7ad52329d3' 
  AND token = 'San4riLTYlc2YI7YCZLg8+cMC2/bZUuZ81Hd/9kpF/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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