SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '901639add01f8a7f77c9c61faac71265f8c1afc075286bb2aa3f991c5a47f969' 
  AND token = 'n6rCOjZSKQMj4XABZXILkLUpF8mVdQTvqEVzyf58YLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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