SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fc5e85ce0a5243fafc1a4563997dfff30d048fa2920a87703d87d64226769815' 
  AND token = 'daYxWISugGmG1QnBTGYDOZI5X5byIkvcsthkvnpQj44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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