SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aef4eb7161e1a324b961968edf98184507b682b2dfc83903375bc9edb127d753' 
  AND token = 'Z+tePv8lvjYufMKnfHJCovVdP9dt89SaE+0sDU4kmoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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