SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90c20bb1562e2fefc91ca916e81413edcbb927c1a66a960b5f1db731e58ccd27' 
  AND token = 'KnjkNJ39pW79MUwc5nLKNHlCNy22SvC+0HU11RPQ6Hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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