SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a5756a787054908390c2190ee922526b8f903233206d18189b08f55aad9a787' 
  AND token = 'nlLcGzJqZRGwYSGldQO7P9Oopj42Q7uAVDhAQVQ8rDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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