SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d481cebcb02528c097485109b2f87f57e9a4796fb53758035db268ebad0f2ce' 
  AND token = 'w52plMNfWAp6dMHvu6DyWHbybls1plaSbw8Mp952cb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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