SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f8cf08a0cba59c9eb033f98147e75f9ccfe04e541ccb03870ca67b046ea7510' 
  AND token = 'xIm0UKioUu1xT8kJrwsaXKdgAiRqD866TeSOiJo88DI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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