SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89cc3da29a24a010970a4467d2575ecb045300f3f6136e3dbd009cbbb2283e22' 
  AND token = 'urnWEnWJxpkHpLwy7pLip7aKt9ohkNtLwHEUefz1kK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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