SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc8dd52d7e421a9727d060d63a98655f6d7f0d959d93c5568e5b2b23455de88c' 
  AND token = 'g75v/YVqsjBHvoNEPJNvVk7f4ZKWN5XnZk8+xxTVWwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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