SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29e85d0b458f0847ed50134ef6f18cbdc70705c31d013e3cbcf84de6df861524' 
  AND token = '5PaINA9wi2nRYBljGXLmQBNLpGI8poxd48zPztUj9H8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}