SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29c91a9dd73c312ba5cc1592d565d4ff945fd2b36b8c369d57791d8afb2432cc' 
  AND token = 'LWmf37nbzOWpkqYOq9l0qi8ZAvwjAJ7oHkYrEgTJLzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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