SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19ecbd04f28044d51c93bb319296668371309e0ab5c9ed747541f59e54e9f547' 
  AND token = 'vBdgSlnPqnpKYNDezkcFXikuV0TXGk12cB9bCNNUndE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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