SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6da4306951aea947bc696db829ec9b20ecb960ec24f2ef1ab9f911144301a35f' 
  AND token = 'ght9bTXtjpAGNux09P4bfhkNVXMqvIocUgy0gO4OsnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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