SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25ac879c2ae173c64f49f37b7728116620f5adbc48f475c03412a0a123438e9c' 
  AND token = '3C1vzYLy1+hOIBwxdvU01qyf+jMSV3hnvXmOhclONsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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