SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b645fea6e380c0ad90d579422625eb1e3c81b17844eed6781e3e0103a4d592c' 
  AND token = 'hqT2MgwjuLtuQFuU6VEPoQpthOHb12yEAf+P+EsicbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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