SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'beed70e0740a1bf8fed4bcc8f4a05b0d2904836b03d8c330b233e4ed296cb801' 
  AND token = 'MNi8XhgO2ytYWqmHng0zAYvT3kXIXvnathf6RnVIOOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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