SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81fadcc52b2b24cc4b99558b0fdbfd770f1a8eec58d3d5d783450ea62611fc36' 
  AND token = 'hVDDaFv+zsfdcddX45EYbVxUuWxRH2WYWtLlsGqzMkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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