SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '800ab3dcbd45db06af7fc1697d459601cd8445aa67bc8455390516dea218ca47' 
  AND token = 'hVyjlrz8p1MhLgqKPTGyzHzRZgRA8n0A1JKx7arPtB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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