SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd2ac945d82b30b14e2fee1c83f1b9b4fc47cf00af574283288cce8b87f5ee2f4' 
  AND token = 'Q6ZaEkIpS8Suj1czQPLS04SYPFAsThD/vsRUsFaecmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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