SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd99ebde9f112e6853644fa8bf16db3a532349a07634a4f8d64cf9afbe0a00ff0' 
  AND token = '/apWpSbzH/fBDAXaJqb0YqvvkzrY6V5+WjMgFtQ/ojQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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