SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '104daa4f64bc65af96f4496b720bc66376fea8a15b0d3836b7848e0a70d985c4' 
  AND token = 'AwEKiSwzyKVh+h+7D0AAH49fZ/gemIxhqQbBBbQCI0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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