SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3e9675160a453a58618c936c79dae9fe7e69576baec4901629239968e816009' 
  AND token = 'JSmrQ0qmf5OoxoJZhY9TrSFUx9I1h1NQ/Cz+vRl7EMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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