SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5828e7d99914816f34b799fd179cd87eb249142c1b975bd85bd063047dad905d' 
  AND token = 'uvU5HD6AMb4UqGLk8F5/avqwsIWpNhu4ow8JgOBLg9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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