SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c6988b9606284606654ad22bb10070b42311935b5c6d5f5dbd5a9a5a72f8e38f' 
  AND token = '7i/5ZTNQHGLMFB/+8Pxebnkh13HZ26jQzsiTSMo4esQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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