SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b28ae4a39ca085a3ed29c84dc35c8b72ad796ad7baf3913b52c14349bff20730' 
  AND token = 'F/vTxKnO6jYvG6wXswf8u7Fg8F1ZF6GFL0EKecBSvAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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