SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a835bc0382aa256c9ad4eb0f3595a215a5dcc06923e7defcfe761675ac9b100' 
  AND token = 'mo8shxUF6oBpPHj8cKPvefKsNTq31+Pe/0/MfLTlR7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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