SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef934dddc5710db658646751e42bddb7d51499b3aab0f7b46d8e615a8a420ff9' 
  AND token = '0n0wYj80nTxuWsrV5AYsPDl+8N18BUt/LzcgC7rNroI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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