SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '815365f95ecb7f497b91cf2a939c5a90f41555ec70a3dfcc149b9de284395b21' 
  AND token = 'dxdvMCazcuefMCqZrm43oXljsJ8BrGIYQsWyIvWuaJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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