SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff2fe6b058789c6650ace075915c4d06d794ff07b5eff5b8579fe0823cac2253' 
  AND token = 'K+QcRNyQDYISbMF/DvaziLgywIQFZyUqKKJ8hP8kilE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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