SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad8d370021830d1cb273cbbadbfb98c42ebe5cf35b9fd330ad9594dfabf41c92' 
  AND token = '/xRVtYXSANuBUcLg1nf5FHufjUr6zu5Mpkh/B5h983I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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