SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff89007afd1549d1a792836d5b6a607cc24b33c1275385159976f86dcfd73a30' 
  AND token = 'gRHZ6zhahO9Q9Ge6fOksWk8BMs5wH3O4zJk0edZKy/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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