SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0c00a8d4567d1e71c66b84ed361bd8716ed33484cc476b2288dba8faa4b51f1' 
  AND token = 'TBhskELIfyj0BKpfTf28E0ZW7BssK1YBvkGO8bELSSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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