SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89bfcaa4f89aaae50135dad2038f73886cdbfe3e837ae123675b5d8ed067fb79' 
  AND token = 'pAB7TGSNmStNpwu7Ms4rc2P9UphIr040AvWIXo3AmvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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