SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26a950e4b861bf9e30bb36087637c4f4c20f4cbb5632fa37616d6ce3aa0c0cf1' 
  AND token = 'bJRItbX+Jyr51GRQO+X/QkXBnIpxW+ztDhNHq5xY294=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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