SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0845490cb6d5358fc334b07e126a780795b9a0a5a76df96eab589a36ed71c2c3' 
  AND token = '+i6aVhi1FwT1J0YyzMINw5hWrMBJJWv2YCN8w+CWem0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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