SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1968e48fc4048bcabb0d88e0c6710efdc4ce6c06950a5d186146b5c640383f13' 
  AND token = '55LsyIrNAOIRzBev8+6SJYRBlE6cDCjf8hTGYBZKzk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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