SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08ab673499342fbf8e15837752b79b11c96571a75eba87041ecafe5690ae2d6f' 
  AND token = 'DSDjYjI8kBse5wJlweXwUGgUj6LSLjDkjGVA0pZncBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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