SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aacf7df54794ab455ba3aa1363d260b95e858848ff386081d93bf67fa4e089ac' 
  AND token = 'im2cKcw0bMIHQbSjKgnOKkExBzxi0PpRB9e0fZfCPQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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