SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '973379f3f63c529b1240bd1d2eb15bc50a32d95bfdc112d21850df282235abd0' 
  AND token = 'qJjXTV5jVXCGtKTIkzicoRtVov0aKcCU2h3qIDt+a7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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