SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4e6cdb6fd0d83d323e03a02e670ec4438316342308e08895c848092c1503e97' 
  AND token = 'dPz/zKPoKYkba3rR/hYB3ti4yHFf3CJWKJ1MqOGJfuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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