SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efbbe61603a7e97bb1896846937a216673cefe2e0a06b7e60f395c60c6f09f80' 
  AND token = 'wgddGz7W2OidPfFlk7XqkkmBnHzVl/OFMGodzJCjJZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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