SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf28f495ce06d18ba23ffd46ecac2ce7527f8e311945355d6b1fd286f3accfe9' 
  AND token = 'TXGXNt1OYcV2euGQ/32RJCbS3OxZAifsn1TC+qTi4CA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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