SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '469047a2f2aa86654b1845132e925915ee86cb750c861e060667f004a4a5590d' 
  AND token = 'z5SVg6oErTGFuYlMTldkVEdPN9hPBnSrV4rbdj3BPx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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