SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3eb533622f49457af54f134fb347082f5d5eabd43ad52c70a0cbfcae0b5d409d' 
  AND token = 'QDDlpu6tuDU06ZQ5EUCcz2pQVUFfCv3bRbre3cmJFqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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