SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce3ea64a07bcce8a1ed255dde9988151fe3b3cbc430e60a11a87f8df1a228850' 
  AND token = 'p/iNToTQS2Bwe/kVIGdGjdJyBqHbWv1P+kVzfWwMbk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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