SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '870da15ce11c010356e4deb98b8ad519ada34ae95547bfdf72d2b257938a2f56' 
  AND token = 'xmfzJjA8EH0g1HX6fBCOjION7LMeVEyWGzVKIi11HOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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