SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8cf6f0e965cf39d08776a01cef97edf3cf2157707a3036a3b59974289a82558' 
  AND token = 'nlhPgOl9dll/q/ahulKk/9Lvi7znGVKhHA6TQnzqMd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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