SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab36b81d0432de30e5d8382eec5b204f088d069caeb36f28ec70c28922bb8e66' 
  AND token = 'mFsC8G+jb9AiZT02yzVulc4+FPQ5aet7eFbtwWDe9FU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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