SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcd5f1ba558043b14bcb5f42aa0f38eda04e6d57fe4fcbd2597cc47621688b90' 
  AND token = 'TjW75D1pZWFYWQdG9Tfjgkapu/bU1mZCS7Hk5KfE8DY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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