SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '285f9933f08e8855457ec05b7d11c6c6cc8bfaf88daab08d262ae616637a79c4' 
  AND token = 'xRYct5AAhYLqDjqQXAnzt1gV9f/bjELZKnqyX8bzcvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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