SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70abb8786b4d9926d29de64d9265d2cf909c7d53f5ee7ab190138a4559da23bd' 
  AND token = '1ag68xQCAqojUi3lRQrDJculZjxAw2wnsCWOUKx9h+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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