SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30f945669148fe153f263921c40bc9fc51ac9c7548ac7d5e7cb47999aa5c6336' 
  AND token = 'vNfB8qtRRvigaS69LMUCg1G/4HtNSct1AqRQKHbZwr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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