SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f0761b49c75c341d4e110d065f54907f46bf8c9b177edb2cbde930ff939def6' 
  AND token = 'f4qLtYltFhvOFrFli++QZ8nJAirlogpPHPVjX/E9R/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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