SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9e9266b4a39c7389969084a46d1496fc6dd708a96193807bc73bac86d35e8e6' 
  AND token = 'OMdDGA64cnxBZZhDWRZF7svyfG0Y4miWb2dGsNYsaXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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