SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6da9ac47f663ff9bdc060c11aec5581fe03983fda2896b9d46ee3f30b006e50f' 
  AND token = '09j56kmkqCvNiAYcSsmv+R/Wsg7fYArUMSSzkn5wLhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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