SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1789909e8f36ef050f451ba17cd2901ba0fa09ed5d43d86d61da2ecdc3f9aaaa' 
  AND token = 'DJlfLHZ7lOhlUC4XnYAAiPC3DYsd6UjwdImxMRaOv2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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