SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3af8e56e0d49aa0842ffa009eeed2fcf6a943d7bad5dc030e06e55b6a7339af5' 
  AND token = 'CEan5gxXDONQ84zTv5DLFiL1Qx3kLrX2oHPccv4QsOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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