SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b7ec4813f8d919dffc3390bfa9fee68a6868ebee10da070d49f52586e54a805' 
  AND token = 'Z3U6xOmYsVrW6ttZFRB+RjAi9j83aQcS5HOyXnt/W8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}