SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4efa99c38b65a4e97df2653d9f9665b1fff1d34949efde3287af7bb3db923210' 
  AND token = 'FjoBZljsVXuTk+f+NDJekOo7Zink9MR4dzjTcT5q7js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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