SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8acc03a1d0a13e3c985465b8aab52d4db18ec3832ced3f2d9738f43a16155779' 
  AND token = 'FD8+HkLkgnvP7WaC5hCBiTmwujjPr1sN9Q2isksia4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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