SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5da850f53bd818833038f9e70b03dd05984f35d9fdcb2e26686ce4da189bf729' 
  AND token = 'nqf3yHi7kzZk4GVLm8SbWbLn43HUOlQwcBOzPtnBOzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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