SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c41f93ae7efcac26f5fe984797614deea8d0446d11ee04ac3d617b5fd8f47b3' 
  AND token = 'kDxAFpVNmdSS1rxZK9SklfH+by28IQCBvUMBTYhos3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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