SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '326d27b553e099d3188c35f7da363dede45d2612306b9698a44b71b915848442' 
  AND token = '7wByEdXfWVZrGiveCgetP2SqGvYNfP5lNzcRSQDZjAk=' 
  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"
    }
  }
}