SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '544e36bd1205e4c1f46bbc1515ee5b010cdf4c8e94536e3764ac5108ee04822a' 
  AND token = 'quc16GnbMthQJse50G+LmhfFhwkQdTnTF26VQlKuLfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}