SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6403fae02091fab832c0aab91dbae347d0ce3926fcc254058ade95a901036245' 
  AND token = 'HFp6dlBz9Ci2VEnxJrenpYvBEmKzqDzOttcXg+mcKgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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