SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb29336adb17e183e503e53922e9a92aee24fe84f6a97bd616d14f202f9dc8b0' 
  AND token = 'dioAY9edWmwiWlCbA8gJnbgXIqnVWys4nTlQ9iK658M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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