SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d27651f4e44a02005ab0c6e9f1151558bd079ee963dbf297ccddf51b49e999c' 
  AND token = 'OACi52w8kWgAhYVc2v6T4gNZPLXKFmRLXN+qza+GixA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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