SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd424cd3cfd8ea00451d2844644711d60114b763ba606f381f50f953e661bf53c' 
  AND token = 'bcOubmj975JCZSA5DuIUUC/XjTISQe9Cz1wWex7bj7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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