SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8d3e0b360e3d8f4b245e22c19080c87bd3340c22157e307372e93f49be02a95' 
  AND token = 'd7aO1/QIVc0pXJUo0qTlPmzDnFRzCD5nXb7gegnIByU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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