SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a53ee09c1810338fd4ecdeec13788fa871d58ba09940a0e8e73f933375fc440e' 
  AND token = 'MksoVfFD3nfWgo3u5anTXuzQLCqDCPLGnT2HjkcfTuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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