SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '818f4f8befa8b8ff6f75d9e55a1f5b0050408e87388d2a985a52bec73a3dc20e' 
  AND token = 'lF5Qrj37GVVvXR35PSLsYLZxLIEUicViD4RcA33O/6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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