SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec5667af22f5aa0bb8ee51877ad2ca8f7295d4941152608a78fb22c1f69630a9' 
  AND token = 'xv6VGJwxU2g7YUM35y2xU8ZQkZ45XOKk3Jy+vgBs9AM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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