SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4096c6e85752a6dc8264f42c32242b115686f71afa3e8758d61aaccfa203d2ad' 
  AND token = 'mRm1OHOrpaaHXT2MK9RdgMFvRxKI0B+XwIWFocLRtzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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