SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '788ff03b669939bee65ba87bd6647aa472464ba408354397ad231bb5a847b005' 
  AND token = 'cDh7QWTbwyEUKxvc1Fbl9VaOnPPC0XsuP9AWzy7BM+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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