SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7620876be2da3cbe8f49f05e2877c9d45fbf27b7b15f495f59ca7805d93d90c6' 
  AND token = 'PYgB/YS1OKTTcQLLFjhlwYDxdj18coKOVs2yE7gpX34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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