SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b160b289ef513495e8332171c9e07c1bdeb758543a16c188c2db0cdd23495f3' 
  AND token = 'DzZju5rNf1StEPrk8+Bvq7Dnllsr+XWcfCpi9tvu8KI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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