SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6532c31a7d3d8428cff5d3b5be3c9f6aa0667f1d7261dea1d668599edc104de4' 
  AND token = 'B0+qfh0TaKinG5ZVBwRSv2pxDaK3T9OcVVJdZAbygiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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