SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd021bca311e0c2fbf1ac1737cc49e871a14bd702641bba8784105c57320ddc8e' 
  AND token = 'YwMvhpBReGUWDQwOfwvdSS9sSchpuWaDJ6IQGuUbAj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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