SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3677f6908fe0109d2589e64ab9beb7e78e36388249aa8be049a0fec518f1c6d5' 
  AND token = 'tHjOYQWWRNk5eDYpBYZjQmMbqhtrf2VTbRmGjrESU6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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