SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '404840fc3ecf3af412b26902aa5d6052826a75b0ee98543f3f605245a7e1c2d3' 
  AND token = '59sSUm7rxhrvImn6pNqNcm43mmPd5KZUGgWu5kWJEX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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