SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b687cf662149167d0c13b8e7aac7e89e5d7df092a07492f8b97af02d61fdd95' 
  AND token = 'HBNnX6WmjUUUpOtVR16lN50SRPDG+kfZHY51gIs5Hfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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