SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58eb5fdd066bb84e40dc866a4848d86ba544eedfe3c977741ad1ba53794b15ff' 
  AND token = 'Mhup0B/aWax6dGVpJHg8E3FxSe75HJhZ0j/3MjEBpzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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