SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dd8797bf7168f1b139b6adf18c97bea6e03fbb29948fb565f4185e1c576e36d' 
  AND token = 'UsTBFNzv5iYQo3JzElgytwJHG7YALhRxcyQIf/cVKEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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