SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b0e939133cfb78c6831cdba4907b7a4f72dbdea32ee399d6a037ee9d402ecda' 
  AND token = 'N8B7qzIwTDEh48GQQ6FdWoNnWBPXtuNtLRl8ui4vAlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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