SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '465c3e41922b270c3b069d470c122fe5f01ceefcde77d8281052844052d23723' 
  AND token = 'LCw8plKs89pftiqOzEWa0FuQanuzIAzmSkXQGM4BP50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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