SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49148f613346d948a5450991bf04668d7f13f48a6be5b2fef5e13458087da614' 
  AND token = '9nXP7+Jb9lxZTLzrm/XrcY1fG+CHU14adwYJ7nXuBbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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