SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e69b68b43e6a0a786aed513732fb0f9bceec23b4399aa7c0646ead079722e468' 
  AND token = 'n4TYXkXJrbYhiFy+YXnyOaQ9pWTSZS5DNVxnPvDuAJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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