SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1f94fde422107afe088f9144ae60a4fa0c1bd1053b1a2a908297a78fac823e2' 
  AND token = 'I8LhWNdmQv9f3+Zg2OON5zQVD8vYMsyy6HbnrwwzwVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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