SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '709380890de709745389b8ec823c08cc010c372c82fbfaf6cfb37e5b0026610e' 
  AND token = 'H1IhNWbftfjXxGD+mOgOsKg7L1bajhkxqP6F8Z7g/hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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