SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a301470f7b1112caad954427584121dd8409e7c04d6e1f2f2cb64548c9b09641' 
  AND token = 'yujDsm1CiaJyLlECwxZ8Fi8Bg9ragL9fINQVs271hRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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