SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e73ce167d2a1a3658cb03b8750f8254d67767a68afcf9b2267732ecd89816c6' 
  AND token = 'Rt/LK8jW+nRtDhuqDzHxgFsRA3qGNAd8szGjVCHQky8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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