SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '808c82eab5c8efdde425e72dc3f9de634742f691aaf08b469275e5ec05e8394e' 
  AND token = 'Oagb4QeSUY/ert/M0nTeMhEa9Zo4PYBKo7RSfM/e/Eg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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