SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd72baa5ccaaf1897126480651649fd9679e99dd32da8893889d2711a5ab87cb9' 
  AND token = '5jjpxaHVEOIDqxfaNulfLHw4XVMxb9zG5OU8eXQSjcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}