SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55689925675493104295122bbed266b8ebe30bb47f1d56d643773279085580fa' 
  AND token = 'IpSW3jVUksI/quvG+3c5ns5XOS5zSxg6fF6D4KMqqZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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