SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4be618f0dfdf3919f66dca70eeab42e5061fae1187cee016af886a2a3be03eb2' 
  AND token = 'UpgeZbtDhdKdhXMIUyWmD/RP9kyRuHRXs4u7TExV9Jc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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