SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73189fa531a1a474df91264dfdcbc6cbaaad1eb1d24590ec2d044715184dc1f6' 
  AND token = '0y5wepU0hcStKdB+n7awE5CnQo0Uen6/WQZJ5A9ck3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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