SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5efe9c37a92b4ec99d813b395df7f583a82a1fec39cdc06afa3cb78d04f093c' 
  AND token = 'umRLtktKkTY3/f7Qp1K9pTw5/7Y/Wmm0cEm+jURCJSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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