SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6e31abf2e966a9e8a02beb4783268857841f488141ef4e41ee84b31083bd5c0' 
  AND token = 'N1DdoNukhIzqKExjVT2p7nZU5ev8/w6p+zlofRyanUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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