SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91d4fa8a71fe808be09d5b4a23a23780ab2482b45edef5b4f1dd7b780a53fa84' 
  AND token = 'U8Qy457i9PHAVUxSYqGR+AmlT7iC8HYlv3wbwCyF7Bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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