SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a7f7b668a6e6c239320b5eaf5a83de5bb417132f302e7ae473b5f5cf53c8404' 
  AND token = 'HwcLXob2iWFflAhZP+prsHg98ttlqzYMVCYAcn/sZtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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