SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31ab54470eda8609b7e9a443683de1faf432c2ac50bfda2a64650ab18f10698f' 
  AND token = '5M4pSydjeiZyFzjVd9GcR2o5nKDnf7tj85/LNBWFRlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00070

JSON explain

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