SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd8fc040345ce078b710a495778294277f219890b19d3ee3e54c92c7817cbda6' 
  AND token = '9nlcRJKXcmvCK/wBvg4HAauX5DgOuHKGRo+WCKs5Fxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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