SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d62dc5cfadebea4768c4569248df0526bd02c5ee7c7d03f173e8370fd5efc2a' 
  AND token = 'cbsTwHBrPQeQMJtRBsdQXLOZAVv6phE4bZDMfznmgYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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