SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaa99d7e0c78eb13ec56cd3acc4245cbfee1d69f6f68aad487c488114d09606a' 
  AND token = 'MtaNfvt7M4SvcQI1vusNvtTv3HuCkVnf0lkAzipvqcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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