SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4452c0d1deabb351824c92c1b89b57281177d0ff75622890b2323c0e5797c938' 
  AND token = '8JS9ftcsfsfyIJty6Uo09hoqgAlnSoW70QkipCxGfMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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